Download Inorganic Manual Sp2022 (ver 1.220102)

Inorganic Chemistry Laboratory: Experiments in
Coordination and Solid-State Chemistry
Spring 2022
Dr. Michael Lufaso
Associate Professor of Chemistry
University of North Florida
Copyright © by Michael Lufaso
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TABLE OF CONTENTS
Page
1. Safety and Techniques ...................................................................................................2
1.1. Safety and lab procedures ......................................................................................3
1.2. Laboratory notebook ..............................................................................................7
2. Laboratory Experiments.................................................................................................9
2.1 Equipment and instrumentation overview .............................................................10
2.2 Synthesis and characterization of [Co(NH3)4CO3]NO3 and [Co(NH3)5Cl]Cl2 .........13
2.3 Synthesis and characterization of linkage isomers [Co(NH 3)5ONO]Cl2 and
[Co(NH3)5NO2]Cl2 ............................................................................................................................................22
2.4 Synthesis, characterization, and resolution of enantiomers of [Co(en) 3]3+ ............27
2.5 Synthesis of [Ru(bpy)3](BF4)2 and preparation of an organic LED ......................34
2.6 Synthesis of an air sensitive compound: copper(I) chloride ..................................42
2.7 Synthesis and characterization of a high temp. superconductor: YBa 2Cu3O7-x .....49
3. Molarities of concentrated reagents .............................................................................53
4. Filter paper ...................................................................................................................54
5. Instrumentation instructions: .......................................................................................55
5.1. Fourier Transform Infrared (FTIR) spectroscopy.................................................56
5.2. UV-Vis spectroscopy ............................................................................................61
5.3. Conductivity meter ...............................................................................................64
5.4. Polarimetry ...........................................................................................................66
5.5. Magnetic susceptibility .........................................................................................69
6. Guidelines for preparing reports ..................................................................................78
6.1. Laboratory report 1 guidelines..............................................................................81
6.2. Laboratory report 2 guidelines..............................................................................85
6.3. Laboratory report 3 guidelines..............................................................................93
6.4. Laboratory report 4 guidelines..............................................................................94
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1.1 Safety
Safety is the top priority in the inorganic chemistry laboratory. The potential of risk is present
in laboratory experiments. Experimental procedures were deigned to minimize potential hazards.
When in doubt about any situation in the lab, consult with your instructor. In addition to these safety
guidelines, there are also experiment-specific safety considerations. Although an accident is rare,
it may happen. If an accident occurs notify your instructor immediately. In the event of an
evacuation (e.g. fire alarm) know how to evacuate and where to assemble. Evacuate at the nearest
stairwell and meet near the fountains near building 39.
The use of headphones or equivalent is not allowed in the laboratory. Performing unauthorized
laboratory experiments is firmly prohibited. Unauthorized experiments present unacceptable and
unknown safety hazards.
Departmental safety regulations are listed below and must be followed:
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Door to lab closed
All students wearing safety goggles or glasses with safety shields
All students wearing either long pants to the ankle of a lab coat
No open‐toed shoes
No eating, drinking
Long hair, dangling jewelry/necklaces out of the way
Fume hood sash at lowest setting when in use and students are working at a minimum of 6
inches into hood.
Tripping hazards on floor are out of the way
No obvious spills on countertops that are not being addressed
Gloves being used with strong acid/base work
Waste bottles present, labeled, and being used by the students
Gloves removed when handling cell phones, calculators, and personal items
The syllabus has additional details on the penalty for not following the safety regulations.
When using chemicals:
 Read the label carefully
 Understand the potential hazards of all chemicals before using them
 Never taste a chemical or solution
 Avoid inhaling vapors and keep open vessels containing organic solvents in a hood at all
times
 Dilute acid by adding acid to water. Never add water to concentrated acid
 Keep reagent bottles tightly capped when not in use
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The label on the chemical bottle is the easiest thing to check. Labels do not provide in-depth
quantitative information but will usually tell you the types and levels of hazard posed by a chemical.
NFPA (National Fire Protection Association) information (often found in a
diamond):
The Health Hazard Section is blue; Fire Hazard is red, Reactivity is yellow, and Specific Hazard is
white. For the first three sections, in each case they are rated from 0-4, with 4 indicating the highest
hazard level. For more information about the chemical, its hazards, proper handling and emergency
response, use the MSDS. MSDS: Material Safety Data Sheets provide more information about
chemical toxicity. The content and quality of MSDSs varies with the manufacturer, so it may be
worthwhile to look at multiple sheets. MSDS’s are available on-line (www.hazard.com).
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Chemical Spill Prevention & Waste Collection
Spill Prevention
At all times you should work carefully to avoid spills. This means:

Good Housekeeping: you are less likely to tip something over when your area is neat

Keep lids on reagent bottles when not in use

Flasks with liquids should be clamped or supported to prevent tipping. A thermometer in a
flask should be clamped rather than just set in the flask. A thermometer (or stirring rod or
spatula) left sticking out of a flask will increase the chances of it tipping.
Spills and Splashes
If a chemical contacts your skin, rinse the area with water. If necessary, use the safety shower. Any
clothing saturated with chemicals must be removed; this is not a time for modesty.
If you are splashed in the face but have splash-proof goggles on, use the eye wash, leaving your
goggles on so that the chemicals do not get rinsed into your eyes.
If you are splashed directly in the eyes, use the eye wash. For maximum effectiveness you must
have your eyes open; use your fingers to hold them open if necessary.
Waste Collection
Because different institutional disposal methods are required for different classes of chemicals, we
will always collect our chemical waste into different labeled bottles. Always place waste in the
appropriate waste bottle, for your safety and for the sake of the environment. Waste bottle types in
our labs are:

Aqueous Waste: While some aqueous waste can go down the drain, most of the aqueous waste
generated in the experiments must be collected in waste containers. Use the sinks in the fume
hood if you are informed that waste is okay to go down a drain. This will serve to minimize
laboratory odors.

Non-Halogenated Organic Waste: compounds which do NOT contain a carbon-halogen
(fluorine, chlorine, bromine, iodine) bond.

Halogenated Organic Waste: compounds which contain a carbon-halogen bond.

Heavy metals: Solids or solutions containing heavy metals are often collected separately so that
the heavy metals can more readily be recovered.

Toxic or Reactive Substances: If substances are particularly toxic or reactive, they may be
collected separately to insure safe handling.
Waste bottles should not be overfilled. Pay attention to the fill level of waste bottles. If a bottle is
getting full, notify the instructor so that a new waste bottle can be provided. Please remember to
fill out the waste label, full name of chemicals, when you add to a new waste bottle.
Used weighing dishes are disposed of in the trash can.
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Safety Equipment
Introduction
Fire is the most common serious hazard that one faces in a typical chemistry laboratory. While
proper procedure and training can minimize the chances of an accidental fire, you must still be
prepared to deal with a fire emergency should it occur. You should NEVER attempt to fight a
fire. Fire extinguisher types, as well as the proper procedures to follow should a fire occur, are
described below. It is not a comprehensive guide.
Stop, Drop, and Roll
If your clothing is on fire STOP, DROP and ROLL on the ground to extinguish the flames. If you
are within a few feet of a safety shower, you can use these instead. If a labmate catches on fire
and runs out of the lab in a panic, tackle them and extinguish their clothing.
Fire Classification
The National Fire Protection Association (NFPA) classifies fires into five general categories
(U.S.):
 Class A fires are ash-producing materials like burning paper, lumber, cardboard, plastics etc.
 Class B fires involve flammable or combustible liquids such as gasoline, kerosene, and
common organic solvents used in the laboratory.
 Class C fires involve energized electrical equipment, such as appliances, switches, panel
boxes, power tools, hot plates and stirrers. Water can be a dangerous extinguishing medium
for class C fires because of the risk of electrical shock unless a specialized water mist
extinguisher is used.
 Class D fires involve combustible metals, such as magnesium, titanium, potassium and
sodium as well as pyrophoric organometallic reagents such as alkyllithiums, Grignards and
diethylzinc. These materials burn at high temperatures and will react violently with water, air,
and/or other chemicals. Handle with care!!
Some fires may be a combination of these! Fire extinguishers have ABC ratings on them. These
ratings are determined under ANSI/UL Standard 711 and look something like "3-A:40-B:C".
Higher numbers mean more firefighting power. In this example, the extinguisher has a good
firefighting capacity for Class A, B and C fires. NFPA has a brief description of UL 711 if you
want to know more.
Basic Types of Fire Extinguishers
The two most common types of extinguishers in laboratories are pressurized dry chemical (Type
BC or ABC) and carbon dioxide (CO2) extinguishers:
Response to a Fire
You should NEVER attempt to fight a fire. However, in the event of a fire, you should respond in
the following manner.
1. Shout to notify your instructor that there is a fire.
2. Your instructor will indicate whether evacuation is necessary.
3. If we evacuate, we will:
 Exit the building calmly via a stairwell that is the opposite direction of the fire
 Assemble in the fountain area near building 39 (J. Brooks Brown Hall)
 Pull the fire alarm on the way out.
4. If necessary, be sure to stay low and avoid smoke.
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1.2 Laboratory Notebook
1. Purpose of lab notebooks
Individual lab notebooks should provide a complete and permanent record of all aspects of all
experiments. It should be possible at any time in the future, using the information contained within the
lab notebooks to replicate exactly what was done in any given experiment. The lab notebook should
produce a record of a scientific experiment that is understandable to a knowledgeable reader and can
be used to repeat the experiment and, presumably, get the same results.
2. Style of Notebook
The basic lab notebook should have three characteristics: 1) it should be bound and sturdy, 2) the
paper should be of high quality (durable and long-lasting), and 3) pages should be numbered. There
are a wide range of notebooks that meet these criteria available for purchase at the UNF bookstore or
equivalent location.
3. Lab Notebooks
1. Lab notebooks are not designed to be works of art, but accurate records of everything done and
observations about the experiment (and you may find it helpful to include what you thought). Use
it as a real-time log rather than a report written after the fact. Avoid writing data or observations
on scraps of paper for later inclusion into your notebook. This could lead to errors and to missing
information. In certain cases, it may even raise questions regarding the accuracy of your records.
2. Notebooks should be numbered and have a clear indication on the cover and binding of your name
and the inclusive dates (start and end dates).
3. Provide your current contact information (e.g. phone number, e-mail address) as well as the name
of the lab professor and their contact information. This can be placed on the outside or inside cover
of the notebook.
4. One or two pages should be set aside at the beginning of each lab notebook to permit the creation
of a table of contents. If different types of experiments are contained in the same notebook, an
index grouping experiments by type may be used.
5.
All writing must be easily legible, both to you and others. Record all information in permanent
blue or black ink. Do not use pencil or brightly colored ink.
6. If corrections must be made, the incorrect information should be crossed out with a single,
indelible line (wrong data), permitting the original entry to be read but making it clear that you
wish to delete it. One should never erase or white-out data.
7. All information should be entered in chronological order.
8. There should be no blank spaces except in so far as this is necessary to permit you to start a new
experiment on a fresh page. In this case, a line should be drawn through the blank space.
9. No pages should ever be removed from a lab notebook. All pages should be consecutively
numbered.
While entering information into your lab notebook, keep in mind that it may prove to be an
important record for you (or in certain cases another person many years from now). Short-term
memory is just that, short-term.
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4. Entries for Individual Experiments
For each experiment, your entry should include the following:
1. A unique numerical designation and a descriptive title. This will enable you and the lab professor
to quickly find the right notebook and page for this experiment.
2. Date of entry: Each entry for a given experiment should be dated. If an experiment lasts several
days, a new date should be added. Pages should not be skipped but an indication of where a given
experiment is continued should be provided at the end of a day’s entry (e.g., “continued on page
23”). The page the experiment is continued on should also reference the page the experiment was
continued from (e.g., “continued from page 18”).
3. Purpose: A few sentences summarizing what you hope to accomplish with this experiment written
before you arrive to the lab to do the work.
4. Safety: Include a brief overview of safety hazards associated with reagents used in the experiment.
5. Methods: Include sufficient details to allow you or a fellow student replicate your procedure
precisely without a copy of this lab manual.
 Include reagent information (company, catalogue number, purity, and lot number), solutions (date
made, name of person that made it), and any special pieces of equipment. You may wish to include
sketches of your experimental apparatus.
 If you were assisted in any way by others, their names and description of assistance should be
entered.
 Note: You may be able to indicate that some additional details can be found in previous
experimental write-ups. In that case it is not necessary to repeat the details. However, be specific
about where that information can be found, and be sure that the information is still accurate.
 A reagent table should be prepared listing reagents and chemical formulas, amounts in grams and
moles, and other pertinent information [mp, bp, density, amount used (g & mol), notes etc.].
 Pre-lab calculations should be completed before the day of the experiment and be clearly shown
with appropriate significant figures and units on numbers.
6. Results.: all data, all experimental calculations, and all incidental observations go directly into
your lab notebook. “Data” refers to primary data as well as any subsequent transformations or
analyses. Since these are results that you observed, any words used to describe them are typically
provided in the past tense (e.g. “The solution turned blue.”).
 All data should be entered whether or not you feel that some data should not be included in your
subsequent data analysis. If you have a clear reason for excluding the data from your analysis,
provide a reason that is stated explicitly and would be generally accepted (e.g., >2 standard
deviations from the mean or resulting from an obvious technical error (e.g. an incorrect chemical).
 There are several cases in which it is not practical to place the actual raw data in your bound
notebook. However, even in those circumstances it is essential to provide an indication of where
the data can be found. It is acceptable to store certain forms of data in a loose-leaf notebook and/or
an electronic medium (e.g. flash drive) with a clearly labeled with your name. Be sure that
information in your notebook is adequate to permit a reader to find the data.
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2. Inorganic Chemistry Laboratory experiments
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2.1 Equipment and instrumentation overview
Inorganic chemistry has a rich and distinguished history starting from the ancient times
involving the smelting of copper, production of bronze weapons, golden jewelry, and clays
in building materials. The various stages in human history track the progress in inorganic
chemistry: The Stone Age, the Bronze Age, the Iron Age, and the Atomic Age. The
development of modern inorganic chemistry has many far-reaching consequences that can
be found in most aspects of daily life, from pigments in paint, automobiles, catalysts for
production of fuel and other chemicals, batteries, LCDs, cell phones, computers,
medicines/anti-tumor agents, etc.
The primary purpose of a chemistry laboratory is to acquaint an experimenter with the
various techniques and manipulations to prepare both known and new materials. Some
techniques needed to synthesize and characterize inorganic compounds will be familiar to
you (e.g. weighing, stirring, preparing solutions, collection of IR and UV-Vis spectra, etc.),
whereas other techniques may be new to you (e.g. magnetic susceptibility, glassblowing,
air sensitive techniques, etc.)
In first day of the inorganic lab you will become familiar with the laboratory spaces and
some of the equipment and instrumentation that will be utilized throughout the semester.
A few basic experiments will illustrate the use of the equipment and instrumentation.
1. Syllabus and locker distribution
a. Laboratory safety agreement
2. Instrumentation overview, read instructions for operation of instruments
a. Top-loading and analytical balances and cleaning procedures
b. UV-visible spectroscopy - Beer’s Law experiment on [Co(H2O)6](NO3)2
i. Details on next page
c. Conductivity, Hanna Instruments HI9093 conductivity meter (time permitting)
d. Infrared (IR) spectroscopy (time permitting)
i. Collect an IR spectrum of NaNO3 and [Co(H2O)6](NO3)2
ii. Assign and label major peaks
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UV-visible spectroscopy - Beer’s Law experiment on [Co(H 2O)6](NO3)2
The absorbance of a solution follows Beer’s Law. Beer’s law is A = εbC where A is
absorbance (no units), ε is called the molar absorptivity (L mol -1 cm-1 or M-1 cm-1), b is
the path length (cm), and C is concentration (mol/L or M). The typical cuvette path
length is 1.00 cm. A plot of absorbance vs. concentration is linear and the slope is equal
to the molar absorptivity.
Prepare 10 mL solution at the given concentration of an assigned solution. Ensure all
the solid is dissolved. Collect a spectrum from 326 to 800 nm. Find peak(s). Save a pdf,
print and retain the spectrum. Record the wavelength(s) of maximum absorbance (λmax)
and absorbance(s). Tabulate data from each of the other students.
#
Name
1
2
3
4
5
6
7
8
9
10
11
12
Concentration,
assigned (M)
0.0200
0.0288
0.0363
0.0438
0.0513
0.0588
0.0663
0.0738
0.0813
0.0888
0.0963
0.1038
Concentration,
prepared (M)
λmax,1 (nm)
(~511 nm)
A
Calculate the molar absorptivity for your single data point. Prepare a Beer’s Law plot
of absorbance vs. concentration (M) (all data points) for each peak. Include slopes and R2
of the trendlines. Determine the molar absorptivity (extinction coefficient, ε) from the
slope of the line in the Beer’s Law plot for the peak near 511 nm.
Calculate the percent error of your molar absorptivity data point as the experimental
value and the slope as the accepted value. The equation for percent error is given below.
𝑃𝑒𝑟𝑐𝑒𝑛𝑡 𝐸𝑟𝑟𝑜𝑟 =
(𝑒𝑥𝑝𝑒𝑟𝑖𝑚𝑒𝑛𝑡𝑎𝑙 𝑣𝑎𝑙𝑢𝑒 − 𝑎𝑐𝑐𝑒𝑝𝑡𝑒𝑑 𝑣𝑎𝑙𝑢𝑒)
× 100%
𝑎𝑐𝑐𝑒𝑝𝑡𝑒𝑑 𝑣𝑎𝑙𝑢𝑒
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Conductivity measurements of KCl solutions
Prepare 25.00 mL solution of KCl at an assigned concentration. Measure the
conductivity and record the units. Calculate the molar conductivity for each KCl solution.
Calculate the average molar conductivity of all solutions. Briefly comment on the obtained
versus expected values of molar conductance for KCl solutions.
Graph the measured conductivity vs. concentration for the KCl solutions using all lab
data points. Examine the units and ensure the x-axis values all have the same units.
#
1
2
3
4
5
6
7
8
9
10
11
12
Name
Concentration (M)
0.0050
0.0067
0.0083
0.0100
0.0117
0.0133
0.0150
0.0167
0.0183
0.0200
0.0217
0.0233
Conductivity
Units
Reference instrumentation instructions for the conductivity meter to calculate the molar
conductivity. It is recommended to use Excel.
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Synthesis and characterization of [Co(NH3)4CO3]NO3 and
[Co(NH3)5Cl]Cl2
Introduction:
Experiments involving the aqueous preparation of cobalt(III) complexes have been a familiar feature in
many textbooks written for use in the inorganic chemistry laboratory.1 Coordination compounds of Co(III)
have been of interest because their complexes, kinetically inert, undergo ligand exchange very slowly
compared with various other transition metals. The metal complex Ni(NH3)62+ reacts very rapidly with water,
undergoing a ligand substitution reaction, to form Ni(H2O)62+. The analogous reactions of Co(NH3)63+ and
Cr(NH3)63+ occur slowly in aqueous solution. Ligand field and molecular orbital theory may be used to
qualitatively explain the differences in reactivity.2 The slow reactivities of octahedral complexes have led to
extensive investigations of these compounds. In this experiment, you will prepare the coordination
compounds [Co(NH3)4CO3]NO3 and [Co(NH3)5Cl]Cl2 via ligand substitution reactions. The structures of the
octahedrally coordinated ions are shown in Figure 1.
Figure 1: (left) [Co(NH3)4CO3]+ and (right) [Co(NH3)5Cl]2+.
Part I: Synthesis of [Co(NH3)4(CO3)]NO3·0.5H2O
Cobalt nitrate, Co(NO3)2, is deliquescent and tends to absorb atmospheric water vapor. Upon exposure
to atmospheric moisture, cobalt nitrate forms a hexahydrate with the formula Co(NO3)2·6H2O, which can be
represented as [Co(H2O)6](NO3)2.
The synthesis of [Co(NH3)4CO3]NO3 involves the following unbalanced equation,
[Co(H2O)6](NO3)2 + NH3(aq) + (NH4)2CO3 + H2O2 → [Co(NH3)4CO3]NO3 + NH4NO3 + H2O
Co(II) complexes react very rapidly by ligand exchange, thus a possible first step in the reaction is:
Co(OH2)62+ + 4 NH3(aq) + CO32- → Co(NH3)4CO3 + 6 H2O
The intermediate tetraamminecarbonatocobalt(II) is then oxidized by addition of H2O2 to form
[Co(NH3)4CO3]+, which combines with the nitrate ions in solution to form the neutral compound
[Co(NH3)4CO3]NO3. Under aqueous conditions, the precipitate formed is a hemihydrate, which is a chemical
compound with one molecule of water for every two molecules of the main formula. The crystal structure
has been solved and is represented as [[Co(NH3)4CO3]NO3]2·H2O or in terms of a single cobalt-containing
molecular unit, [Co(NH3)4(CO3)]NO3·0.5H2O.3-5
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Part II: Synthesis of [Co(NH3)5Cl]Cl2
Compounds with a carbonato ligand (CO32-) are useful intermediates in the synthesis of coordination
complexes. The carbonate ion is easily removed by the addition of HCl and the decomposition of the
carbonate forms carbon dioxide. The carbonate ion is a bidentate ligand and its removal leaves two open
coordination sites. Water molecules or chloride ions may occupy the open coordination sites. Water is not a
particularly strong ligand and addition of ions such as X-, NH3, or NO2- leads to the replacement of these
coordinated water molecules.
The synthesis of [Co(NH3)5Cl]Cl2 involves the following equations,
[Co(NH3)4CO3]+ + 2 HCl → [Co(NH3)4(OH2)Cl]2+ + CO2 (g) + Cl[Co(NH3)4(OH2)Cl]2+ + NH3 (aq) → [Co(NH3)5(OH2)]3+ + Cl[Co(NH3)5(OH2)]3+ + 3 HCl → [Co(NH3)5Cl]Cl2(s) + H2O + 3 H+
Part III: Characterization
Characterization of the metal complexes will involve several techniques: 1) UV-Vis spectroscopy, 2)
infrared (IR) spectroscopy, 3) Conductivity measurements, 4) Magnetic susceptibility measurements.
UV-Vis spectroscopy is used to probe the electronic structure. The type of absorption (i.e. d-d transition,
charge transfer, etc.), if the absorption is spin-allowed or spin forbidden, if it has a centrosymmetric or noncentrosymmetric geometry may be determined from the magnitude of the molar absorptivity coefficient. The
wavelength of maximum absorbance and its changes can be related to changes in the magnitude of the crystal
field splitting parameter Δoct and the four factors that affect this parameter.2 If multiple d-d absorptions are
observed, the appropriate Tanabe-Sugano diagram may be used to determine the value of Δoct. Pertinent
literature values are: [Co(NH3)6]3+ Δoct = 22,900 cm-1, [Co(H2O)6]2+ Δoct = 9,300 cm-1. When ligand
substitutions are performed, the spectrochemical series can be used to predict if the Δoct decreases or increases
and if the wavelength of maximum absorbance shifts to a longer or shorter wavelength.
Infrared (IR) spectroscopy is used to examine the frequencies of the vibrational modes of the molecule.
For example, absorption is anticipated at frequencies characteristic of the stretching and bending modes of
the CO32-, NH3, and NO3- groups in [Co(NH3)4CO3]NO3. The spectrum of the cobalt-bound CO32- in the metal
complex is slightly different than for the ion in Na2CO3, whereas the absorption bands resulting from the
vibrational modes of the NO3- counterion in the metal complex are more similar to those observed in NaNO3.
The IR spectrum of [Co(NH3)5Cl]Cl2 consists of absorptions primarily attributed to the NH3 groups.
Stretching modes between heavy atoms (e.g. Co-N, Co-Cl) are, in principle, also measurable, but occur at a
lower frequency than can be observed in a typical infrared spectrophotometer (650 – 4000 cm -1). The Co-N
stretching in trans-[Co(en)2(mtzt)2]NO3 (en=ethylenediamine and Hmtzt=1-methyl-1-H-1,2,3,4-tetrazol-5thiol) were reported to occur in the range 233 to 397 cm-1.4 The Co-N stretching in [Co(NH3)5Cl]Cl2 were
reported to occur in the range 440 to 486 cm-1 and Co-Cl stretching at 275 cm-1.5
Conductivity measurements enables the determination of the number of ions in solution. Two electrodes
are immersed in a solution and a potential is applied between them, resulting in a current produced in the
14
external circuit that connects the two electrodes. The electrical communication between the two electrodes
in solution involves the movement of ions in the solution. Assuming no appreciable solution electrolysis
occurs, the magnitude of the current observed generally obeys Ohm’s Law: V = iR, where V is the applied
potential, i is the measured current, and R is the resistance of the solution. The experimentally determined
conductivity reflects contributions from all ions present in solution that are mobile and can carry the current.
The conductivity is concentration dependent, thus measured values for different solutions are not easy to
compare directly. The molar conductivity (sometimes termed equivalent conductivity) is the quantity that is
used. The molar conductivity is symbolized by Λm, and is defined as the solution conductivity (κ) normalized
by the concentration (C): Λm = κ /C. Each singly charged ion has a molar conductivity near 60 Ω-1 cm2 mol1
. A solution of the 1:1 electrolyte has a conductivity near 120 Ω-1 cm2 mol-1. Large and slow moving or
highly charged ions tend to result in a lower conductivity value. Species involving H+ and OH-, i.e. acids and
bases, have hydrogen-bonding chain conduction mechanisms and deviate from the typical range. The
following table lists a range of molar conductivities for various ion conductors in aqueous solution.6
Number of
ions
2 (1:1)
3 (1:2)
4 (1:3)
5 (1:4)
molar conductivity, Ω-1
cm2 mol-1
96-150
225-273
380-435
540-560
The following compounds, [Co(NH3)6]Cl3, [Co(NH3)5Cl]Cl2, and [Co(NH3)4Cl2]Cl, have a different number
of ionizable chloride ions and thus number of ions in solution, and thus exhibit different molar conductivities.
Conductivity measurements enable one to distinguish between the compounds.
Magnetic susceptibility measurements enable one to determine the magnetic properties and if a
compound is diamagnetic or paramagnetic, and if paramagnetic – the number of unpaired electrons, and if it
is high-spin or low spin. Whether a complex is high-spin or low spin can be rationalized in terms of the
geometry, oxidation state of the cobalt and d-electron count, and identity of the ligands.
Experimental Section: Safety
Investigate the properties and briefly list in your lab notebook any special hazards
associated with each of the following reagents: cobalt (II) nitrate hexahydrate
[Co(H2O)6](NO3)2, concentrated aqueous ammonia NH3(aq) (NH4OH), concentrated
hydrochloric acid HCl, ammonium carbonate (NH4)2CO3, hydrogen peroxide H2O2.
15
Experimental Section: Techniques
Review safety, basic glassware, weighing using a top-loading balance and analytical
balance, quantitative transfer, using a pipet, vacuum filtration, volumetric flasks, conductivity
measurements, infrared spectroscopy, UV-Visible spectroscopy.
Experimental data required
Due to equipment bottlenecks, this experiment will be conducted in groups. Typically,
this will be groups of three or four students.
Table 1: Data required for each compound.
IR
UV-Vis Conductance Magnetic
[Co(H2O)6](NO3)2
[Co(NH3)4CO3]NO3·0.5H2O
[Co(NH3)5Cl]Cl2
NaNO3
Na2CO3
KCl
MgCl2
Shared
Group
Group
Shared
Shared
N/A
N/A
Individual
Group
Group
N/A
N/A
N/A
N/A
Shared
Group
Group
N/A
N/A
Individual
Shared
Shared
Group
Group
N/A
N/A
N/A
N/A
Individual = Individually collected by each student.
Group = Group data, each group of students collects data.
Shared = Shared data. Pair of students within group collects data. Send data to be shared with entire class
via Canvas.
N/A = Not applicable, do not collect data.
Experimental Procedures
Part I: Synthesis of [Co(NH3)4(CO3)]NO3·0.5H2O
Ammonium carbonate, used as a smelling salt, is an irritant to the mucous membranes and
reactions should be kept in a fume hood as much as possible. Before weighing, open the bottle in
the hood to remove ammonia vapor from the bottle. The powder tends to clump together and it may
be necessary to break apart the (NH4)2CO3 using a rubber mallet/plastic bag and/or grind using a
glass mortar and pestle prior to weighing. Cobalt nitrate hexahydrate is hygroscopic and will absorb
atmospheric moisture. Use a top loading balance, if available, for the synthesis and an analytical
balance for the characterization steps.
Dissolve 0.208 mol of (NH4)2CO3 in 60 mL of H2O in a beaker under constant stirring. Add 60
mL of concentrated aqueous NH3 (ammonium hydroxide, NH4OH). Pour this solution, while
stirring, into a solution containing 0.0515 mol of [Co(OH2)6](NO3)2 in 30 mL of H2O. Slowly add 8
mL of a 30% H2O2 solution dropwise (Warning: H2O2 is a strong oxidizing agent that can cause
severe burns. Use proper gloves while handling. If a spill occurs, wash the affected areas
immediately with water.). Concentrate to about 80-90 mL using a hot plate. The use of an
evaporating dish may be used in place of a beaker to facilitate evaporation. Using an alcohol
16
thermometer and ensuring the bulb doesn’t contact the stir bar, maintain the temperature of the
solution near 85°C. Do not allow the solution to reach 100°C and boil. Add 5 g of (NH4)2CO3, in
small portions, during the course of the evaporation. Cool to about 5°C in an ice water bath and
then isolate the red crystalline product by suction filtration into a clean side-arm Erlenmeyer flask.
Transfer the filtrate to a separate 250 mL Erlenmeyer flask and retain. Wash the product with a
small amount of ice-cold water and then with a small amount of 95% ethanol. Place the product in
a preweighed sample bag, weigh the product and sample bag. Use these data later to determine the
percent yield. If needed, further reduce the volume of the retained filtrate and perform a second
evaporation using the evaporating dish and a second filtration.
Retain, for the next experiment, the product in a weighed and labeled (initial and last name,
complete formula compound, and date) sample bag. Leave the top of the sample bag open and prop
in
a
beaker
to
let
the
sample
dry
over
the
next
week.
Store
in
the
“Inorganic Samples” drawer. Discard the filtrate wash solution in the appropriate hazardous waste
container in the fume hood. Do not tightly cap the waste bottle, for safety reasons, because of the
decomposition of carbonates and pressure increase inside a closed container. Retain the product for
the next part of the experiment.
Part I: Characterization
Data in Table 1 can be collected on any of the experiment days. The IR, UV-Vis spectra, and
conductivity data may be collected before, during, or after the synthesis of [Co(NH3)5Cl]Cl2. Utilize
your time wisely.
IR: Time permitting on week 1 of this experiment, collect IR spectra of NaNO3, Na2CO3,
[Co(H2O)6](NO3)2, and [Co(NH3)4CO3]NO3·0.5H2O using the Perkin Elmer Spectrum 1 Infrared
Spectrometer or Shimadzu IR Affinity I (FT-IR). Ensure the peaks are labeled.
UV-Vis: Time permitting on week 1 of this experiment, prepare an aqueous solution of
[Co(NH3)4CO3]NO3·0.5H2O, using a 25 mL volumetric flask, with a concentration near 0.00500
M. Data must be collected on the same day as solution preparation, since these are not stable
complexes if stored in water. Collect the UV-Vis spectrum in a plastic cuvette from 315 nm to 800
nm. The absorbance should be between 0.5 and 1.0. Record the wavelength of maximum absorption
and absorbance. Adjust the concentration and prepare a second solution if the absorbance is outside
that range.
Conductivity: Time permitting on week 1 of this experiment, test operation of a Hanna
Instruments HI9093 conductivity meter by measuring the conductance of tap water, deionized
water, and 0.0100 M KCl. Ensure the molar conductivity of KCl is within the expected range for
17
a 1:1 salt as listed in the conductivity measurement instructions. Measure on the same day the
conductivity of the solution of [Co(NH3)4CO3]NO3 prepared for UV-Vis. During this week or
next week measure the conductivity of 0.00500 M solutions of KCl and MgCl 2. Use these data to
calculate the molar conductivity values.
Part II: Synthesis of [Co(NH3)5Cl]Cl2
Dissolve 5.0 g of [Co(NH3)4CO3]NO3·0.5H2O in 50 mL of H2O and slowly add concentrated
HCl (5-10 mL) until all of the CO2 gas is evolved. Neutralize the solution with concentrated
ammonium hydroxide until the vapor above the solution tests basic with red litmus paper. Add an
excess of about 5 mL of the concentrated aqueous NH3 (NH4OH). Heat for 20 minutes, avoiding
boiling, to form [Co(NH3)5H2O]3+. Note any color change as one of the coordinated water
molecules is replaced. Cool the solution slightly and slowly add 75 mL concentrated HCl. Reheat
to about 75 °C for 20-25 minutes and note any change in color. Cool to room temperature and
watch for the formation of a precipitate. Wash the compound several times by decantation with
small amounts (1-2 mL) of ice-cold DI H2O. Isolate the crystalline [Co(NH3)5Cl]Cl2 by suction
filtration. Wash with cold 95% ethanol (3-4 mL) and dry by pulling air through the crystals for
several minutes. The solutions used for washing should be cold to prevent the loss of product by
redissolving. Transfer [Co(NH3)5Cl]Cl2 to a weighed sample bag, then place partly open bag
containing sample in a drawer to dry over one week. After one week, reweigh the product and
sample bag, and use this to determine the percent yield. Retain the product in a labeled (initial and
last name, complete formula of the compound, and date) sample bag.
Discard the filtrate wash solution in the appropriate hazardous waste container in the fume
hood. Do not tightly cap the waste bottle, for safety reasons, because of carbonate decomposition
and pressure increase in a closed container.
Characterization
Collect an IR spectrum of [Co(NH3)5Cl]Cl2. Ensure the peaks are labeled. Prepare a 0.00500
M aqueous solution for conductance and UV-Vis measurements using a 25.00 mL volumetric flask.
Collect the UV-Vis spectrum in a plastic cuvette from 315 nm to 800 nm. Measure the conductance
of deionized water and [Co(NH3)5Cl]Cl2 and calculate the molar conductivity. Compare to the
molar conductivity of simple 1:1 and 1:2 chloride salts.
Complete characterization of all data found in table 1. Record and summarize the raw data in
the following supporting information tables. These data are needed for the calculations.
18
Supporting information tables for raw data.
Include these completed tables as supporting information. Create your own numbered
tables for calculated values in the results and discussion section.
Table S1: Summary raw data, synthesis.
Formula
Mass of limiting
reactant used in
synthesis (g)
[Co(H2O)6](NO3)2
[Co(NH3)4CO3]NO3
Mass of product
obtained from
synthesis (g)
Formula
[Co(NH3)4CO3]NO3
[Co(NH3)5Cl]Cl2
Table S2: Summary raw data, UV-Vis.
Formula
Mass used
to prepare
solution
(g)
Volume
of
Solution
(mL)
Absorbance
Maximum(s)
Wavelength(s) of
maximum
absorbance (nm)
[Co(H2O)6](NO3)2
[Co(NH3)4CO3]NO3
[Co(NH3)5Cl]Cl2
Table S3: Summary raw data, magnetic susceptibility.
Formula
Length
(cm)
Mass (g)
Temperature
(°C)
R0
[Co(H2O)6](NO3)2
[Co(NH3)4CO3]NO3
[Co(NH3)5Cl]Cl2
Table S4: Summary raw data, conductance.
Formula
Mass (g)
[Co(H2O)6](NO3)2
[Co(NH3)4CO3]NO3
[Co(NH3)5Cl]Cl2
KCl
MgCl2
19
Volume of
Solution (mL)
Conductance
(specify units)
R
References
(1) Angelici, R. J. Synthesis and technique in inorganic chemistry; W.B. Saunders, 1977.
Szafran, Z.; Pike, R. M.; Singh, M. M. Microscale Inorganic Chemistry; John Wiley and
Sons, Inc., 1991. Schlessinger, G. Carbonatotetramminecobalt(III) Nitrate. In Inorganic
Syntheses, McGraw‐Hill Book Company, Inc., 1960; pp 173-175. Schlessinger, G. G.
Inorganic laboratory preparations; Chemical Publishing Company, Inc., 1962. Walton,
H. F. Inorganic Preparations; Prentice-Hall, Inc., 1948. Tanaka, J.; Suib, S. L.
Experimental methods in inorganic chemistry; Prentice-Hall, Inc., 1999. Jolly, W. L. The
synthesis and characterization of inorganic compounds; Prentice-Hall, Inc., 1970. Dixon,
N. E.; Jackson, W. G.; Lawrance, G. A.; Sargeson, A. M. Cobalt(III) amine complexes
with coordinated trifluoromethanesulfonate. In Inorganic Syntheses, Holt, S. L. Ed.;
Wiley-Interscience, 1983; p 103. Richens, D. T.; Glidewell, C. Linkage isomerism: an
infra-red study. In Inorganic Experiments, Woollins, J. D. Ed.; Vol. 2; Wiley-VCH,
2003.
(2) Housecroft, C. E.; Sharpe, A. G. Inorganic Chemistry; Pearson Education Limited,
2018.
(3) Bernal, I.; Cetrullo, J. The phenomenon of conglomerate crystallization. XVIII.
Clavic dissymmetry in coordination compounds. XVI. Structural Chemistry 1990, 1 (2),
227-234.
(4) Talebi, S.; Amani, V.; Saber-Tehrani, M.; Abedi, A. Improvement of the Biological
Activity of a New Cobalt(III) Complex through Loading into a Nanocarrier, and the
Characterization Thereof. ChemistrySelect 2019, 4 (45), 13235-13240.
(5) Chen, Y.; Christensen, D. H.; Faurskov Nielsen, O.; Pedersen, E. NIR-FT-Raman
spectra of some cobalt(III) ammine complexes. Journal of Molecular Structure 1993,
294, 215-218.
(6) Girolami, G. S.; Rauchfuss, T. B.; Angelici, R. J. Synthesis and technique in
inorganic chemistry: a laboratory manual; University Science Books, 1999.
20
Prelab: Synthesis and characterization of [Co(NH3)4CO3]NO3 and [Co(NH3)5Cl]Cl2
Clearly show work for credit.
1) Calculate the mass in grams for 0.208 mol of (NH4)2CO3.
2) Calculate the mass in grams for 0.0515 mol of [Co(OH 2)6](NO3)2.
3) Calculate the theoretical yield (in g) of [Co(NH 3)4CO3]NO3·0.5H2O in this
experiment.
4) Calculate the mass, to the nearest 0.0001 g, of [Co(OH 2)6](NO3)2 needed to prepare
25.00 mL of a 0.00500 M solution.
5) Calculate the mass, to the nearest 0.0001 g, of [Co(NH 3)4CO3]NO3·0.5H2O needed to
prepare 25.00 mL of a 0.00500 M solution.
6) Calculate the mass, to the nearest 0.0001 g, of [Co(NH 3)5Cl]Cl2 needed to prepare
25.00 mL of a 0.00500 M solution.
7) Calculate the mass, to the nearest 0.0001 g, of KCl needed to prepare 25.00 mL of a
0.00500 M solution.
8) Calculate the mass, to the nearest 0.0001 g, of KCl needed to prepare 25.00 mL of a
0.01000 M solution.
9) Calculate the mass, to the nearest 0.0001 g, of MgCl 2 needed to prepare 25.00 mL of a
0.00500 M solution.
21
Linkage Isomers: Synthesis and Characterization of [Co(NH3)5ONO]Cl2
and [Co(NH3)5NO2]Cl2
Divalent cobalt is more stable than trivalent cobalt for simple salts of cobalt, with only
a few salts of Co(III) known (e.g. CoF3). Formation of a coordination complex stabilizes a
higher oxidation state as evidenced by many known octahedrally coordinated complexes.
In this experiment, you will prepare two classical linkage isomer compounds,
[Co(NH3)5ONO]Cl2 and [Co(NH3)5NO2]Cl2 .1
Figure 1: Structure and color of nitro [Co(NH3)5NO2]Cl2 and nitrito [Co(NH3)5ONO]Cl2
linkage isomers.
1) One synthesis scheme of [Co(NH3)5Cl]Cl2 involves the following unbalanced
equations:
Co2+ + NH4+ + ½ H2O2 → [Co(NH3)5(OH2)]3+
[Co(NH3)5(OH2)]3+ + 3 HCl → [Co(NH3)5Cl]Cl2(s) + H2O + 3H+
2) Synthesis of [Co(NH3)5ONO]Cl2 and [Co(NH3)5NO2]Cl2 involves the following:
[Co(NH3)5Cl]2+ + H2O → [Co(NH3)5H2O]3+ + Cl[Co(NH3)5H2O]3+ + NO2- → [Co(NH3)5ONO]2+ + H2O
[Co(NH3)5ONO]2+ → [Co(NH3)5NO2]2+
22
Synthesis and Experimental Procedure:
All reactions should take place in a fume hood. Part I may be skipped if sufficient or
close to sufficient amount of [Co(NH3)5Cl]Cl2 is available from a previous experiment.
Scale reagent amounts and solvent in consideration of solubility.
Part I: chloropentaamminecobalt(III) chloride, [Co(NH 3)5Cl]Cl2
Prepare a solution of 0.0935 mol ammonium chloride NH4Cl in 30 mL of concentrated
aqueous ammonia in a 250 mL Erlenmeyer flask. While stirring with magnetic stir bar, add
0.042 mol of cobalt(II) chloride hexahydrate. While continuously stirring, slowly add 8 mL
of a 30% H2O2 solution (CAUTION: H2O2 is a strong oxidizing agent that can cause
severe burns. Use gloves! Wash affected areas immediately with water!). When evidence
of further reaction has ceased, slowly add 30 mL of concentrated HCl. Heat the solution
using a hot plate. Maintain a temperature of about 85°C for about 20 minutes. Do not allow
the solution to boil. Cool the solution slightly and then place in an ice water bath. Isolate
the crystalline product by suction filtration. Wash the product with a small amount of icecold water. The total volume of the wash should not exceed 15 mL. Wash with 15 mL of
cold 6M HCl. Dry in a drying oven for 10-20 minutes and then weigh the product to
determine the percent yield. Allow the sample to continue to dry on the lab bench or in the
drying oven before collecting an IR and UV-Vis spectra at the end of the laboratory session.
Discard the filtrate wash solution in the appropriate inorganic waste container in the fume
hood. Don’t tightly cap the waste bottle.
Part II: pentaamminenitritocobalt(III) chloride, [Co(NH 3)5ONO]Cl2
Heat a solution (do not boil) of 8 mL of concentrated aqueous ammonia in 80 mL of
water. While heating and stirring, add 0.020 mol of ‘dry’ [Co(NH 3)5Cl]Cl2 or 0.024 mol
‘wet’ [Co(NH3)5Cl]Cl2. Continue heating, below boiling point, and stirring until the
product dissolves. Add an additional small amount of 1:10 ammonia:water if needed. This
may take 10-15 minutes. If you observe the presence of a dark brown to black precipitate
of cobalt oxide, filter it off. Cool the solution, in an ice bath, to about 10 °C. Add 2 M HCl
slowly while keeping the solution cold until it is neutral as determined by litmus or pH
paper. Add 5.0 g of sodium nitrite followed by 5 mL of 6 M HCl. Cool the solution in an
ice bath for approximately an hour, then filter the precipitated orange-salmon pink crystals
of [Co(NH3)5ONO]Cl2. Wash with 20 mL of icewater then 20 mL of 95% ethanol. Allow
it to dry on the lab bench for 10-15 minutes before collecting an IR spectrum and UV-Vis
23
spectrum. Do not dry in a drying oven. Discard the waste in the appropriate waste container
in the fume hood. Retain the powder sample in labeled sample bags.
[Co(NH3)5ONO]Cl2 is not stable and will isomerize to [Co(NH3)5NO2]Cl2. Ensure you
have sufficient time in the laboratory session to collect the IR spectrum of the product on
the same day as the synthesis.
Pentaamminenitrocobalt(III) chloride, [Co(NH 3)5NO2]Cl2
In the solid state [Co(NH3)5ONO]Cl2 will isomerize to [Co(NH3)5NO2]Cl2, even at
room temperature, given sufficient time.2 Dr. Fred Basolo, winner of the Priestley Medal
(the highest honor conferred by the American Chemical Society), reported on the kinetics
and mechanisms of these isomerism reactions in the first paper published by the American
Chemical Society (ACS) journal Inorganic Chemistry. 3
Characterization:
IR spectra: Collect IR spectra each week over at three weeks of laboratory periods.
Look for any changes in the data over time as [Co(NH3)5ONO]Cl2 isomerizes to
[Co(NH3)5NO2]Cl2. Utilize IR data for [Co(NH3)5Cl]Cl2 from a previous experiment, if
available. Collect an IR spectrum of [Co(H2O)6]Cl2 as time allows (any week).
UV-visible spectra: Collect a UV-visible spectrum (~0.005 M) each week over at three
weeks of laboratory periods. Utilize a UV-Vis spectrum for [Co(NH3)5Cl]Cl2 from a
previous experiment, if available. Collect a UV-Vis spectrum of [Co(H 2O)6]Cl2 as time
allows (any week). Note: it may be necessary to adjust the y-axis absorbance scale
manually, due to an intense absorption near 325 nm. In the second or third of the three
weeks of the experiment, prepare a 1:50 diluted solution (~1.00×10 -4 M
[Co(NH3)5NO2]Cl2) and use glass or quartz cuvette. Collect a UV-Vis spectrum from 315
nm to 700 nm to resolve the peak near 325 nm.
Magnetic susceptibility: Collect magnetic susceptibility data during one of the three
weeks, as time allows, for [Co(H2O)6]Cl2 and Co(NH3)5ONO]Cl2 / [Co(NH3)5NO2]Cl2.
Utilize magnetic susceptibility data from previous experiment for [Co(NH 3)5Cl]Cl2.
24
IR spectra
CoCl2∙6H2O
NaNO2
[Co(NH3)5Cl]Cl2
[Co(NH3)5ONO]Cl2 (week 1)
[Co(NH3)5ONO]Cl2 /
[Co(NH3)5NO2]Cl2 (week 2)
[Co(NH3)5NO2]Cl2 (week 3)
UV-Vis
spectra (0.005
M diluted)
N/A
N/A
N/A
Magnetic
Susceptibility
Shared
Shared
Use
previous*
Indiv./group
UV-Vis
spectra
(0.005 M)
Shared
N/A
Use
previous*
Shared
Indiv./group
Shared
Shared, select
any one week
Shared, select any
one week
Shared
N/A
Shared
Indiv./group
Shared
Table 1: Checklist for data to be collected for this experiment. *Note, data from previous experiment may be
used for [Co(NH3)5Cl]Cl2, if available.
References
(1) Jolly, W. L. The synthesis and characterization of inorganic compounds; PrenticeHall, Inc., 1970. Tanaka, J.; Suib, S. L. Experimental methods in inorganic chemistry;
Prentice-Hall, Inc., 1999.
(2) Penland, R. B.; Lane, T. J.; Quagliano, J. V. Infrared Absorption Spectra of Inorganic
Coordination Complexes. VII. Structural Isomerism of Nitro- and
Nitritopentamminecobalt(III) Chlorides. Journal of the American Chemical Society 1956,
78 (5), 887-889.
(3) Basolo, F.; Hammaker, G. S. Synthesis and Isomerization of Nitritopentammine
Complexes of Rhodium(III), Iridium(III), and Platinum(IV). Inorganic Chemistry 1962, 1
(1), 1-5.
25
Prelab: Linkage Isomers: Synthesis and Characterization of [Co(NH 3)5ONO]Cl2 and
[Co(NH3)5NO2]Cl2
Clearly show work for credit.
1) Calculate the mass in grams for 0.0935 mol of NH 4Cl.
2) Calculate the mass in grams for 0.0420 mol of cobalt(II) chloride hexahydrate.
3) Calculate the mass in grams for 0.0200 mol [Co(NH3)5Cl]Cl2
4) Calculate the mass, to the nearest 0.0001 g, of [Co(NH 3)5ONO]Cl2 needed to prepare
25.00 mL of a 0.00500 M solution.
26
Synthesis, characterization, and resolution of enantiomers of tris(ethylenediamine)cobalt(III)
chloride
Introduction:
The development of coordination chemistry prior to 1950 involved the synthesis and characterization of
metal complexes with monodentate ligands (e.g. Cl-, Br-, I-, CN-, NH3) and bidentate ligands [e.g.
ethylenediamine (en, H2NCH2CH2NH2), oxalate (ox, C2O42- or –O2CCO2–), glycinate (H2NHCH2CO2-), and
carbonate (CO32-)]. Modern inorganic chemistry has greatly expanded the variety and complexity of ligands.
Coordination complexes of Co(III) and Cr(III) have been of particular interest because the complexes
undergo slow ligand substitution reactions compared to complexes of many other transition metal
complexes.1 Many inorganic metal coordination compounds have a coordination number of six. There is the
potential for the formation of isomers, provided the coordination compound lacks an internal mirror plane.
The enantiomers formed in this experiment are isomers that are mirror images of one another. In such cases,
the enantiomers may also react differently with achiral reagents.
In this experiment, you will synthesize several salts based on the Co(en)33+ ion and resolve (separate)
their enantiomers. The synthesis involves the oxidation of a cobalt (II) salt, CoCl2•6H2O. A Co(II) complex
is initially made by reaction of cobalt nitrate hexahydrate (CoCl2•6H2O) with ethylenediamine
dihydrochloride (en·2HCl).
CoCl2·6H2O + 3 en·2HCl → [Co(en)3]Cl2 + 6 H2O + 6 HCl
Next, the acidic solution is neutralized and Co2+ is oxidized by hydrogen peroxide.
[Co(en)3]Cl2 + 1/2 NaOH + 3/2 HCl + 1/2 H2O2 + 3/2 H2O → [Co(en)3]Cl3•1/2NaCl•3H2O(s)
The mixture of enantiomers is resolved by slow and careful crystallization in the presence of the optically
active dianion (+)tartrate [abbreviated as (+)tart]:
27
The [(+)Co(en)3][(+)tart]Cl is less soluble than its (-) enantiomer salt and it preferentially crystallizes out of
aqueous solution, as the pentahydrate, leaving the (-) isomer in solution as shown in the following unbalanced
equation.
[(+/-)Co(en)3]Cl3 (aq) + (+)tart2-(aq) → [(+)Co(en)3][(+)tart]Cl•5H2O(s) + (-)Co(en)33+(aq)
These enantiomers have been examined using 59Co NMR.2
Experimental Section: Safety
Investigate the properties and briefly list in your lab notebook any special hazards associated with each of
the following reagents: cobalt(II) chloride hexahydrate ([Co(H2O)6]Cl2), concentrated aqueous ammonia
(ammonium
hydroxide,
NH4OH),
hydrogen
peroxide
H 2O 2,
ethylenediamine
dihydrochloride
(H2NCH2CH2NH2·2HCl), L-(+)-tartaric acid diammonium salt, (NH4)2(C4H4O6).
Experimental Procedures
Part I: Preparation of racemic tris(ethylenediamine)cobalt(III) chloride:
Add 25 mmol of CoCl2·6H2O, 100 mmol of ethylenediamine dihydrochloride (H2NCH2CH2NH2·2HCl)
and a stir bar in a 250-mL beaker with approximately 25 mL H2O. Stir for a couple of minutes until the cobalt
salt is dissolved completely. The mixture will appear a cloudy pink. Add 200 mmol of sodium hydroxide
pellets and stir. A cloudy orange solution is formed. Continue stir for a few minutes until the sodium
hydroxide is completely dissolved. Add 20 mL of 3% H2O2 (prepare 3% by dilution if a higher concentration
of hydrogen peroxide is available). The solution should darken upon addition of the peroxide. Heat below
boiling (near 90 °C) for a few minutes on a stirring hot plate until the cloudiness disappears. Allow a few mL
to evaporate during the near boiling step to concentrate the solution, then cool slightly and remove the stir
bar from the hot solution with a stir bar retriever. Place the beaker in ice bath and cool for approximately 30
minutes. With a suction filtration apparatus and filter paper, collect the fine orange to yellow-orange needles
that have formed. Make sure to filter the solution while it is cold. Before rinsing the crystals, transfer the
filtrate back to the beaker and, if needed, recover additional [Co(en)3]Cl3 from the filtrate by reducing its
volume and re-cooling. Impurities will also eventually precipitate, for example NaCl with solubility of 0.36
g/mL in water.3 Do not recrystallize and combine products unless the first yield is poor.
Press the solid flat and even on the filter paper and wash it with small portions of a total of 50 mL of
cold 95% ethanol and then small portions of cold 20 mL of diethyl ether. Pull air through the crystals until
dry. Weigh the collected sample and record the yield. Discard the filtrate wash solution in the appropriate
labelled hazardous waste containers in the fume hood.
Note: Save some of the [Co(en)3]Cl3 (at least 0.4-0.5 g) for UV-Vis and IR spectroscopic analyses in lab
session 1 and proceed to the resolution of the tris(ethylenediamine)cobalt(III) ion.
Resolution of the tris(ethylenediamine)cobalt(III) ion
Add 11.5 mmol of [Co(en)3]Cl3•1/2NaCl•3H2O, 15 mmol of L-(+)-tartaric acid diammonium salt, and a
stir bar in a 100-mL beaker and add 20 mL of H2O. Adjust the quantities of both the compounds and solvent
volume if you use a different amount of the racemic mixture due to low yield. Add 35 mmol of sodium
28
hydroxide and cover the beaker with a watch glass. Gently stir the mixture and heat, without boiling, on a
stirring hot plate for a few minutes until the solids completely dissolve, add more H2O if needed. Remove
the stir bar with a stir bar retriever and let the solution cool to room temperature. Cover with parafilm or a
watch glass and store in the inorganic cabinet under the fume hood nearest the entrance. Collect the crystals
by decanting and filtration in the next laboratory session.
Part II: Resolution of the (+)Co(en)33+ ion as the Co(en)3[(+)tart]Cl•5H2O salt
In the previous laboratory session, the resolution of the tris(ethylenediamine)cobalt(III) ion was initiated
by
adding
(+)tartrate
to
the
mixture
of
enantiomers
(or
stereoisomers)
of
tris(ethylenediamine)cobalt(III)chloride. The [(+)Co(en)3][(+)tart]Cl is much less soluble than the (-)
enantiomer salt and preferentially crystallizes out of aqueous solution first, as the pentahydrate, leaving the
(-) isomer in solution.
[(+/-)Co(en)3]Cl3 (aq) + (+)tart2- (aq)  [(+)Co(en)3][(+)tart]Cl·5H2O (s) + (-)Co(en)33+ (aq)
Prepare a filtration assembly and obtain your covered beaker from last week that contains the crystallized
[(+)Co(en)3][(+)tart]Cl·5H2O(s) and (-)Co(en)33+ in solution. Decant the dark orange solution into an
Erlenmeyer flask and retain this solution for an upcoming step. Ensure no wash in the next steps comes into
contact with the decanted solution that contains (-)Co(en)33+.
Isolate the dark orange crystals by filtration. Prepare 20 mL of a 1:1 (vol.) water:acetone solution and a
20 mL portion of pure acetone to rinse the crystals of [(+)Co(en)3][(+)tart]Cl·5H2O(s). Wash the crystals
with the water/acetone solution and then pure acetone. Pull air through the crystals of
[(+)Co(en)3][(+)tart]Cl·5H2O(s) until dry and record the yield.
Isolation [(+)Co(en) 3]I3•H2O
Place 3.9 mmol of [(+)Co(en)3][(+)tart]Cl·5H2O in a 50 mL beaker with 15 mL of water. If necessary,
break up large crystals with a spatula. With continuous stirring with a stir bar, add one (1) pellet of NaOH,
and heat the solution very gently until all of the solids dissolve. Do not boil the solution or heat for more than
a few minutes. While the solution is still warm, add 24 mmol of NaI. Continue stirring for one minute and
then cool in an ice bath. Vacuum filter the crystals and wash with 10 mL of an ice-cold solution of 0.3 g/mL
NaI in water. Wash the crystals with 10 ml of 95 % ethanol and then with 10 mL of acetone. Pull air through
the crystals until dry.
Isolation of [(-)Co(en)3]I3·H2O
Obtain the filtrate solution saved from resolution of the (+)Co(en)33+ ion as the Co(en)3[(+)tart]Cl•5H2O
salt and dilute to 30 mL. Add one pellet of NaOH, gently heat and stir the solution until the NaOH dissolves,
then add 57 mmol of NaI while stirring. Cool the solution in an ice bath, collect the impure precipitate (it
may contain some (+) enantiomer) by filtration, and wash with 5 mL 0.3 g/mL NaI in water. Discard the
filtrate into the waste. Isolate the pure (-)enantiomer by dissolving the precipitate in 35 mL of warm water
(50 ºC). Filter off the undissolved (+) enantiomer and add 5 g of NaI to the filtrate containing the (-)Co(en) 33+.
29
[(-)Co(en)3]I3•H2O should crystallize from the solution on cooling. Collect the precipitate, wash with 5 mL
ethanol and then 5 mL acetone, and then air-dry.
Physical Property Characterization:
Plan experiments in a manner that will minimize waiting time for instrumentation by arranging each of
your experiments in a manner that will minimize conflict with others. For example, the isolation of
[(+)Co(en)3]I3·H2O and the isolation of [(-)Co(en)3]I3·H2O may be done either before, or after the
spectroscopic experiments on the other compounds. Table 1 summarizes the data that is to be collected. Place
initials of the person that collects the data in your group.
IR
spectra
UV-Vis
spectra
Magnetic
Susceptibility
CoCl2∙6H2O
Polarimetry
No
(NH4)2(C4H4O6)
N/A
N/A
[(+)Co(en)3]Cl3•1/2NaCl•3H2O(s)
No
No
[(+)Co(en)3][(+)tart]Cl•5H2O(s)
[(+)Co(en)3]I3•H2O
[(-)Co(en)3]I3•H2O
Table 1: Checklist for data to be collected for this experiment.
An infrared spectrum should be collected for each of the compounds in Table 1. If IR data was collected
in a previous experiment, that data can be reused.
A UV-Vis spectrum (~0.05 M for Co2+ containing compounds, ~0.005 M for Co3+ containing
compounds) should be collected in the range 315-750 nm for each of the solid cobalt-containing compounds.
Magnetic susceptibility data should be collected for each of the solid cobalt-containing compounds. One
data set may be shared between all groups for CoCl2∙6H2O.
Investigate optical activity by polarimetry. Polarimetry data should be collected on L-(+)-tartaric acid
diammonium salt, [(+)Co(en)3]I3•H2O, and [(-)Co(en)3]I3•H2O. For the polarimetry measurement of the L(+)-tartaric acid diammonium salt, use 5 g quantitatively weighed and prepare an aqueous solution in a 25.00
mL volumetric flask. Use a 2 dm polarimeter tube and measure the temperature and observed rotation angle
and sign. For the polarimetry measurement of [(+)Co(en)3]I3•H2O, use ~0.54 g quantitatively weighed and
prepare an aqueous solution in a 10.00 mL volumetric flask. Use a 1 dm polarimeter tube and measure the
temperature and observed rotation angle and sign. For the polarimetry measurement of [(-)Co(en) 3]I3•H2O,
use ~0.54 g quantitatively weighed and prepare an aqueous solution in a 10.00 mL volumetric flask. Use a 1
dm polarimeter tube and measure the temperature and observed rotation angle and sign.
30
References:
(1) Walton, H. F. Inorganic Preparations; Prentice-Hall, Inc., 1948. Schlessinger, G. G.
Inorganic laboratory preparations; Chemical Publishing Company, Inc., 1962. Jolly, W.
L. The synthesis and characterization of inorganic compounds; Prentice-Hall, Inc., 1970.
Angelici, R. J. Synthesis and technique in inorganic chemistry; W.B. Saunders, 1977.
Szafran, Z.; Pike, R. M.; Singh, M. M. Microscale Inorganic Chemistry; John Wiley and
Sons, Inc., 1991. Tanaka, J.; Suib, S. L. Experimental methods in inorganic chemistry;
Prentice-Hall, Inc., 1999.
(2) Borer, L. L.; Russell, J. G.; Settlage, R. E.; Bryant, R. G. Experiments with
Tris(ethylenediamine)cobalt(III) Compounds: 59Co NMR and the Resolution of
Enantiomeric [Co(en)3]3+ Ion and Analysis by Formation of Diastereomeric Ion Pairs.
Journal of Chemical Education 2002, 79 (4), 494.
(3) Pinho, S. P.; Macedo, E. A. Solubility of NaCl, NaBr, and KCl in Water, Methanol,
Ethanol, and Their Mixed Solvents. Journal of Chemical & Engineering Data 2005, 50
(1), 29-32.
31
Prelab: Synthesis, characterization, and resolution of enantiomers of
tris(ethylenediamine)cobalt(III) chloride
Clearly show work for credit.
1) Calculate the mass in grams for 25.0 mmol of CoCl 2·6H2O.
2) Calculate the mass in grams for 100. mmol of ethylenediamine dihydrochloride
(H2NCH2CH2NH2·2HCl).
3) Calculate the mass in grams for 3.90 mmol of [(+)Co(en) 3][(+)tart]Cl·5H2O
4) Calculate the mass, to the nearest 0.0001 g, of [(+)Co(en) 3]Cl3•1/2NaCl•3H2O needed
to prepare 10.00 mL of a 0.00500 M solution.
32
5) Calculate the mass, to the nearest 0.0001 g, of [(-)Co(en) 3]I3·H2O needed to prepare
10.00 mL of a 0.00500 M solution.
6) Calculate the mass, to the nearest 0.0001 g, of [(+)Co(en) 3]I3·H2O needed to prepare
10.00 mL of a 0.00500 M solution.
7) Calculate the mass, to the nearest 0.0001 g, of Co(en)3[(+)tart]Cl·5H2O needed to
prepare 10.00 mL of a 0.00500 M solution.
33
Synthesis of [Ru(bpy)3](BF4)2 and preparation of an organic light emitting diode
Introduction:
Coordination compounds and complex ions of ruthenium have been of scientific
interest because of interesting structural and magnetic properties. The coordination
complexes have a central metal atom that is typically positively charged. The metal atom
is bonded to multiple ligands, which may be a neutral molecule (e.g. H 2O or NH3) or an
anion (e.g. OH-), via coordinate covalent bonds in a Lewis acid-Lewis base reaction. The
charged complexes form ionic bonds to other ions to form coordination compounds. The
complex ion of the coordination compound is placed in brackets within the chemical
formula. In this experiment you will prepare the coordination compound [Ru(bpy) 3](BF4)2,
which has [Ru(bpy)3]2+ as the coordination complex.
Complex cations adopt a range of coordination numbers from 1 to more than 12, but
the two most common coordination numbers are 4 and 6 5. Coordination numbers do not
necessarily define the coordination geometry of a coordination complex. For example, a
four-coordinate complex may adopt a tetrahedral or a square planar geometry. Electronic
and steric factors influence the observed geometry 5. Complex ions have diverse colors that
arise from electronic absorptions. The energies of the d-orbital are no longer degenerate in
a coordination complex, and the splitting depends on the geometry. In the case of a six
coordinate complex in an octahedral geometry, the d-orbitals split into two sets of energies
– a triply degenerate t2g set at lower energy and a double degenerate eg set at higher energy.
The energy gap, or crystal field splitting, between these levels depends on several factors,
two of which are the nature of the ligands and oxidation state of the metal. The crystal field
splitting influences the color, with a smaller crystal field absorbing lower energy light, thus
reflecting shorter wavelength light. The d to d electronic transitions, which may be spinforbidden or Laporte-forbidden, typically have molar extinction coefficients of <1 M -1 cm1
or between 1-1000 M-1 cm-1, respectively, depending on the centrosymmetric or non-
centrosymmetric nature of the molecules 5. For simple absorptions, a color wheel is helpful
in understanding the absorbed and reflected light. Charge transfer absorptions are not
restricted by the selection rules that govern d-d transitions. The probability of these
electronic transitions is high and the absorption bands are intense, with typical molar
extinction coefficients 1000-50,000 M-1 cm-1. There are two main types of charge transfer
34
absorptions: 1) ligand-to-metal charge transfer (LMCT) and 2) metal-to-ligand charge
transfer (MLCT). A MLCT transition occurs than a ligand that is easily reduced is bound
to a metal that is easily oxidized. A LMCT occurs when a ligand that is easily oxidized is
bound to a metal center (typically in a high oxidation state). Studies of the MLCT of
[Ru(bpy)3]2+ has made an impact in photochemistry and photophysics 13.
The first part of this experiment involves synthesizing the coordination compound
tris(2,2’-bipyridine)ruthenium(II) tetrafluoroborate. It will be used as an intermediate in
the formation of a molecular diode. A trivalent ruthenium salt (RuCl 3) is a reactant that is
reduced to Ru2+ using sodium hypophosphite (NaH2PO2) as a reducing agent. The Ru2+
reacts with 2,2’-bipyridine and sodium tetrafluoroborate to form [Ru(bpy) 3](BF4)2. The
2,2’-bipyridine, with two lone pairs of electrons on nitrogen atoms, acts as a bidentate
ligand and forms two coordinate covalent bonds.
Procedure adapted from 14.
Part I: Synthesis of tris(2,2’-bipyridine)ruthenium(II) tetrafluoroborate
Reagent preparation:
I.
RuCl3 from RuCl33H2O
Obtain 3 g of RuCl33H2O and grind to a fine powder in a mortar and pestle. Heat the
powder in a vial without a cap at 100 C overnight, or for at least 3 hours, until the solid
turns from a dark black to a dark brown. Remove from furnace, cool to room temperature,
and store in a desiccator. This will be prepared ahead of time and will be ready for use in
the inorganic laboratory.
II.
NaH2PO2 from H3PO2
In a fume hood, add 3.0 mL DI H2O and a magnetic stir bar to a 50 mL beaker. Clamp
the beaker to a ring stand over a magnetic stirrer. While stirring, add 5.0 mL of H 3PO2
slowly and mix. Obtain 2.0 g NaOH pellets in a weigh boat. Slowly add the NaOH pellets
to the mixture, testing the pH after each addition. The initial pH is acidic. Continue to add
NaOH until the solution is between pH of 6-8. If too much NaOH was added, an additional
drop of H3PO2 could be added to bring the pH into the desired range. This solution can be
shared between students.
35
Synthesis of [Ru(bpy)3](BF4)2
All reactions should be performed in a fume hood. Using an analytical balance, obtain
0.083g of dried RuCl3 (F.W. = 207.45 g/mol) and place in a 25 mL Erlenmeyer flask with
a small stir bar. The RuCl3 is hygroscopic so work swiftly. Make sure to close tightly the
vial if you are not actively transferring RuCl 3. Add 8.0 mL DI H2O and place on top of a
heating magnetic stir plate. Turn the heat on and warm the solution under constant stirring.
Obtain 0.188 g 2,2’-bipyridine (M.W. = 156.19 g/mol) and add to the stirring solution. Use
a micropipette to add 440 µL of NaH2PO2 to the reaction flask. Mark the level of the
solution with a marker and cover the flask with a 1” watch glass. Continue heating to gently
reflux near 80C for 30 minutes, adjusting the heat setting as necessary. For best results
and in order to ensure proper uniform heating, without the risk of boiling, perform this
heating step in a water bath (make sure your flask is secured), while constantly monitoring
the bath temperature. Start at a low heat setting, and get a feel of the behavior of your
heating plate, before cranking it up. Once the temperature reaches ~70 C, start counting
the 30 minutes heating time. Periodically check the water level and add additional DI H 2O
as needed to maintain the volumes in the flask and water bath. Note any color changes that
occur during the course of the reaction and form a hypothesis as to why the color changes.
During the 30 minute reflux period, prepare a solution of 0.333g NaBF 4 in 1.5 mL of
DI H2O, in a small vial or 10 mL flask. Swirl until the entire solid dissolves. When the
reflux is complete, add the NaBF4 solution to the reaction flask and stir for 3 minutes.
Remove the watchglass, and pick up the stir bar using a stir bar retriever. Allow the solution
to cool on the benchtop for about 10 minutes, then place in an ice water bath and continue
to cool for 10 minutes. Note the formation of any crystals and the color.
Set up a Buchner or Hirsch funnel filtration apparatus. Ensure it is clamped to a ring
stand. If needed, trim a section of filter paper to the correct size and place in the funnel.
Moisten the filter paper and turn on the vacuum. Scrape the crystals from the flask into the
funnel. Rinse the beaker with one pipet full (~2 mL) of cold ethanol, and let dry under
suction for about 10 minutes. Preweigh a 3 dram glass vial or weighing bag and collect the
crystals. Weigh the container and crystals, and then calculate the mass of the recovered
36
product. Collect the IR spectrum. Store the crystals for further use and characterization in
a subsequent part of the experiment. Collect the magnetic susceptibility, if directed.
Part II: Assembly of a molecular (organic) light emitting diode.
Introduction:
A light emitting diode is a combination of a p-n junction. As a current is passed through
a semiconductor, electrons from the valence band can be promoted across the energy gap
into the conduction band, a process which allows a semiconductor to conduct electricity.
The electron that was promoted to the conduction band leaves behind a hole in the valence
band. The holes can move in a material, acting as a positively charged particle and are
known as p-carriers. When electrons are the charge carriers, they are referred to as ncarriers. A recombination process may occur when the electron in the conduction band
loses energy and falls into the hole in the valence band. In some instances, the
recombination process results in the production of photons via luminescence.
In conventional semiconductors, a doping process increases the number of p-carriers
or n-carriers. When the n-type semiconductor is brought into contact with a p-type
semiconductor, a p-n junction is formed. The holes on the p-side junction move towards
the n-site, while the electrons on the n-site move towards the p-side. An external voltage
may be applied across the p-n junction, causing it to be biased. A forward bias occurs when
the magnitude of the potential difference between the n-side and p-side is reduced, whereas
a reverse bias occurs when it is increased. A voltage across the p-n junction allows it to
behave as a diode, which only allows current to flow in one direction. An LED is created
by inducing forward bias, and light is given off when the electrons and holes recombine on
both sides of the p-n junction.
The basic structure of an organic light emitting diode (OLED) consists of a thin organic
layer between a transparent anode and a metallic cathode layer. The organic layer consists
of (i) a hole injection layer, (ii) an electron blocking layer, (iii) an emissive layer, (iv), a
hole blacking layer, and (v) an electron injection layer. The transparent layer commonly
used is indium tin oxide (ITO), which is transparent to visible light and has a high work
function which promotes the injection of holes into the HOMO level of the organic layer.
The cathode is metallic and is a low melting gallium-indium alloy. The application of a
37
voltage to the cell, such that the anode is positive with respect to the cathode, results in a
current, consisting of electrons moving from the cathode towards the anode. The electrons
hop from one ruthenium complex to another, reducing the Ru 2+ complex to Ru+1, while
injecting electrons into the LUMO. The ITO oxidizes Ru 2+ to Ru3+, which can be described
as an injection of electron holes into the HOMO. The injected positive holes and negative
charges recombine in the emissive layer, emitting a photon (λ = 630 nm) via
phosphorescence from an excited state Ru2+ formed during the recombination 15.
Ru3+ + Ru+ → Ru2+ + (Ru2+)*
The charge carrier mobility is typically low in organic materials; therefore the layers
must be very thin. The typical thickness is on the order of 100-200 nm, represented in
Figure 1. OLEDs can be very thin and have found use in portable devices including mobile
phones, digital cameras, DVD players, PDAs, and car audio displays.
Fig. 1. Pictorial representation of the stacked layers in an OLED.
Experimental part 2:
Pre-lab preparations:
A) polyvinyl alcohol (PVA) solution:
Prepare a hot water bath with sufficient size to hold a 50 mL Erlenmeyer flask and heat
at 80 - 90 C on a hotplate magnetic stirrer. Obtain 0.15 g of polyvinyl alcohol in a small
weighing dish. Add 5 mL DI H2O and a stir bar to a 50 mL Erlenmeyer flask, clamp the
flask to a ring stand and lower it into the hot water bath. Place a small watchglass over the
38
opening to reduce evaporation. Ensure the water bath fully covers the water level in the
flask, and periodically add water to the bath as needed. Turn on the stirrer and make sure
effective stirring occurs. In very small increments, add the PVA to the flask. Ensure each
portion of the PVA is dissolved before adding the next portion to the flask. After all the
PVA has been added, continue stirring for at least 5 minutes after all the solid has been
dissolved. Remove the flask from the water bath, and pick up the stirring bar using a
magnetic retriever. Cap with a stopper or parafilm. The solution can be stored in a
refrigerator after use.
B) [Ru(bpy)3](BF4)2
Obtain and precisely weigh on an analytical balance 0.035 g of the [Ru(bpy) 3](BF4)2.
Dissolve it in 3 mL of the polyvinyl alcohol solution. Obtain an indium-tin-oxide (ITO)
coated glass and dry for 10 minutes at 110 C either on a watch glass in the oven, or by
laying it flat on the hot plate. Carefully remove the glass using tweezers. Cool to near room
temperature. Using an ohmmeter, determine which side is conducting by placing the tips
of the leads at the corners. The conducting side will have a resistance of 30-50 Ω across
the diagonal of the slide.
Coating method 1: Using double sided tape, secure the ITO coated slide, with the
conductive side up, to the center top of a 2500 RPM fan. Dip the end of a cotton swab into
the [Ru(bpy)3](BF4)2-PVA solution and blot a thin layer of the solution evenly over the
center region of the glass surface. Surround the sample with a splatter shield cover and spin
for 30-60 seconds. Repeat for a total of 3-4 times.
Coating method 2: Using double sided tape, secure the ITO coated slide, with the
conductive side up, to the benchtop. Dip the end of the cotton swab into the
[Ru(bpy)3](BF4)2-PVA solution and blot a thin layer of the solution evenly over the
majority of the glass surface, but leave an uncoated region (~2-4 mm) around the edges.
After coating with either method, dry the coated glass slide using a hot air blower on
the glass for at least 2 minutes. Monitor the evaporation and ensure the surface is
completely dry before proceeding. Prepare a mask using a piece of tape (duct) in aluminum
foil and punch a 1/8 inch hole. In a disposable small pipet, obtain a very small portion of
the liquid gallium-indium alloy and place in a small plastic weigh boat. The liquid gallium39
indium alloy is an eutectic mixture of 75.5% gallium and 25.5% indium and is a liquid
above 16.5 C. Paint, using a cotton swab, the liquid gallium-indium alloy through the
template to add the active metal electrode to several locations on the coated ITO glass.
Using a 4.5-6.0 Volt power supply with leads connected to the terminals, touch the positive
lead to the outside edge of the ITO glass that does not have the [Ru(bpy) 3](BF4)2-PVA
coating. Turn off the lights and carefully touch the negative lead to the gallium-indium
contact circle(s). Record your observations. Try reversing the leads and record your
observations.
Collect the UV-Vis spectrum using the remaining polyvinyl alcohol solution of the
complex. Dilutions will be required. Determine the wavelength of maximum absorption
and the molar extinction coefficient. Use this to determine the type of electronic transition.
References
(1) Housecroft, C. E.; Sharpe, A. G. Inorganic Chemistry; Pearson Education Limited,
2018.
(2) Thompson, D. W.; Ito, A.; Meyer, T. J. [Ru(bpy) 3]2+* and other remarkable metal-toligand charge transfer (MLCT) excited states. Pure and Applied Chemistry 2013, 85 (7),
1257-1305.
(3) Marmon, J.; Lisensky, G.; deProphetis, W. Preparation of an Organic Light Emitting
Diode. https://chem.beloit.edu/edetc/nanolab/oLED/index.html (accessed 2021 Web
Page).
(4) Müller, S.; Rudmann, H.; Rubner, M. F.; Sevian, H. Using Organic Light-Emitting
Electrochemical Thin-Film Devices To Teach Materials Science. Journal of Chemical
Education 2004, 81 (11), 1620.
40
Prelab: Synthesis of [Ru(bpy)3](BF4)2 and preparation of an organic light emitting diode
Clearly show work for credit.
1) Calculate the theoretical yield (g) of [Ru(bpy)3](BF4)2 in this experiment.
2) If the molar absorptivity of [Ru(bpy)3](BF4)2 was 12,500 M-1 cm-1, calculate the
absorbance of a 0.00500 M solution in a 1 cm path length cuvette.
3) Calculate the mass of [Ru(bpy)3](BF4)2 needed to prepare a 10 mL solution with
absorbance of 0.5 in a 1 cm path length cuvette, assuming the molar absorptivity value in
the previous question. Comment on the feasibility of massing this amount.
4) Calculate the molarity of 0.0350 g of [Ru(bpy)3](BF4)2 in 3.00 mL solution.
5) Explain what is meant by the term serial dilution.
41
Synthesis of an air sensitive compound: copper(I) chloride
Metals (e.g. cesium) in low oxidation states are highly reactive and spontaneously ignite when exposed
to air. Similarly, some oxidation states of transition metals are unstable in air. Copper commonly exhibits
both the 1+ and 2+ oxidation states. The Cu(II) ion is generally more stable and commonly observed as a
stable salt. Copper(II) chloride exists in the anhydrous and dihydrate forms. The crystal structure of
CuCl22H2O is shown in Figure 1 and is described as chains of edge-sharing octahedra.1
Figure 1. Crystal structure of CuCl22H2O.
Copper(I) chloride is an inorganic structure with the zinc-blende crystal structure at room temperature. 2
The crystal structure of CuCl at ambient conditions is shown in Figure 2, with the tetrahedral coordination
environments of the copper and chlorine emphasized. Upon heating to 407 °C it transforms into the wurtzite
structure. Upon continued heating, the copper(I) chloride vapor is shown to be exhibit several forms of
clusters CunCln, including (n = 3) Cu3Cl3, which is a trimeric molecule as determined by mass spectroscopy.3
At elevated pressures, several polymorphic forms were determined using high pressure powder diffraction
and the ions changed from fourfold to sixfold coordination.4
Figure 2. Crystal structure of CuCl.
The reduction of Cu(II) to Cu(I) proceeds by the following reaction:
2 Cu2+ + 2 Cl- + SO32- + H2O  2 CuCl + SO42- + 2 H+
42
A compound containing a reduced form of copper, i.e. copper(I) chloride may be prepared, but it is
relatively sensitive to oxidation by moist air. This experiment illustrates the techniques necessary to prepare
and store an inorganic compound with a metal in an oxidation state that is prone to oxidation in air. If the
well-prepared CuCl sample product is not carefully dried and properly sealed, the initially white product will
turn green within a short period of time.
Inorganic compounds that are highly unstable in air or easily affected by moisture are often handled
inside an inert atmosphere glovebox or glovebag, or in some cases a vacuum line. Inorganic compounds
which are less sensitive to air or moisture can be prepared using careful and rapid manipulations of ordinary
laboratory procedures.5 Compounds are often much more sensitive to oxidation when wet. A sample of
copper(I) chloride will remain white indefinitely. If air is admitted to the sample, it will gradually change
color to a green color of an oxidized material. In this experiment, the oxidation of copper(I) chloride to
copper(II) salts is easily observed through a color change in the material (white to green). A portion of the
score will depend on the yield and sample appearance.
Synthesis and Experimental Procedure:
Several storage methods may be utilized in this experiment. One method is to store the sample in a tightly
capped vial sealed with parafilm. An alternative is to place the sample in an open vial, then place the vial
inside a vacuum desiccator containing CaCl2 as the drying agent, then flush the vial with a small amount of
nitrogen gas, cover with parafilm and cap. However, oxygen will slowly diffuse through the cap and vial and
oxidize the sample.
The preferred method to protect an air sensitive sample is to take the dry powder and place it in a glass
ampoule, then seal under vacuum using a torch. The piece of glassware, known as an ampoule, is shown in
Figure 3. The ampoule will be prepared using glassblowing in part 1 of this experiment. Review glassblowing
basics, especially vacuum seals, at: http://www.ilpi.com/glassblowing/ .
43
Figure 3. Schematic representation of glass ampoule preparation.
Part 1: Ampoule preparation and testing for vacuum leaks.
Obtain a length of glass tubing with diameter of ____ mm. One length of tubing can be used to prepare
two ampoules. With guidance from your instructor, light the torch with only the natural gas, then slowly
introduce oxygen until a blue flame is observed. Adjust fuel/oxygen dials as instructed.
Heat the around the circumference of the center of the glass tube to heat the glass and seal off one end
of the tube. This will create two pieces that resemble test tubes. Place in the metal base of the ring stand with
the end overhanging as it cools. Let cool and then clamp vertically in a ring stand. Slightly below halfway,
heat around the circumference of the tube. As it softens, gravity will pull it down, reducing the diameter and
forming a transfer tube. The diameter of the transfer tube (about 8 mm) is about half the diameter of the tube.
The ampoule should resemble the bottom of figure 3. Set aside to let cool.
Your instructor will demonstrate the proper operation of the Schlenk line. The Schlenk line should be
tested for leaks prior to opening the valve to the ampoule. Ensure all valves are closed. The connections from
the individual traps are opened on at a time until the top manifold is open to vacuum. When the vacuum pump
gurgling stops and noise stabilizes, plug in the vacuum gauge and turn it on. Typical readings are below 75
millitorr for the manifold at room temperature and still warming up. Do not operate the vacuum gauge at
ambient pressure for extended periods of time.
Connect the prepared ampoule to the UltraTorr connector on the vacuum manifold. Open the valve
connected to the ampoule, which should result in a brief gurgling at the vacuum pump. The pressure should
initially jump up, then return to a low value with a cease in gurgling from the vacuum pump. If it doesn’t,
ensure the ampoule is fully seated into the UltraTorr connected and the connector is properly tightened at
both ends. Troubleshoot as directed by your instructor. If the vacuum holds, the ampoule may be used in the
next part. If a pinhole leak is present, locate the pinhole and reheat the ampoule to seal the leak and retest.
Do not use a non-tested ampoule in part 2. Each group should have one ampoule. Obtain the mass of the
ampoule.
44
Part 2: Synthesis and characterization of CuCl and sealing under vacuum.
Dissolve 5 g CuCl2▪2H2O in 5 mL of water. Prepare a dilute sulfurous acid solution by dissolving 0.5 g
of sodium sulfite (Na2SO3) and 1 mL of concentrated HCl in about 500 mL of DI water. Retain 10 mL of the
dilute sulfurous acid solution for washing. Dissolve 3.5 g Na2SO3 in 25 mL of water. Add the copper(II)
chloride solution to the 25 mL sodium sulfite solution while stirring. The solution is initially colored, but as
the reduction proceeds it changes to a colorless copper(I) chloride and forms a precipitate.
While the Cu in the solution is being reduced, 1) Collect magnetic susceptibility data for CuCl 22H2O as
time allows, and 2) collect a thermogravimetric analysis (TGA) on CuCl2▪2H2O if directed by your instructor.
Establish a timeline of groups to seal ampoules. When ready, pour the reaction mixture containing the
precipitated copper(I) chloride into 500 mL of the dilute sulfurous acid solution. After an initial stirring, wait
for the copper(I) chloride precipitate to settle and decant off as much of the supernatant solution as possible.
Quickly transfer the residue into a sintered glass funnel set up for suction filtration. Filter and wash several
times with portions of the 10 mL dilute sulfurous acid solution, making sure that the liquid layer always
remains above the product. Before the last wash in this step, turn off and vent the vacuum until you are ready
to wash with other chemicals. If the vacuum pulls air through a sample wet with water the product, the copper
may be oxidized.
Do not wash until a few minutes before your time with the torch and vacuum line is ready. Wash
successively with four 10 mL portions of glacial acetic acid, three 10 mL portions of 95% ethanol, and four
10 mL portions of ether. NOTE: Dispose of the acetic acid and ethanol waste before washing with ether, by
emptying the filter flask by pouring down the sink and flushing with water. Collect the ether waste in the
labeled waste container in the hood. Allow vacuum to pull air for several minutes and ensure the product is
dry after the final ether wash.
Weigh the sample. Retain a weighed portion of CuCl for a prompt magnetic susceptibility measurement.
Transfer the remaining CuCl to the pre-massed ampoule. Using a cotton swab, ensure no product remains
trapped in the seal off portion of the tube, otherwise it may react with the glass upon heating and make the
glass brittle. Your instructor will connect the top of the ampoule to an UltraTorr adapter and show operation
of the vacuum line.
As the sample may still have residual liquid, the valve should be very slowly cracked opened. The sample
should be watched to ensure it doesn’t get pulled into the manifold as and residual liquid volatilizes. When
stable, the ampoule contents should be exposed to vacuum for a couple minutes to ensure that all the water,
ethanol, and ether solvents are removed.
With guidance from your instructor, using a glassblowing torch, carefully seal the ampoule under
vacuum. Note that the pressure from approximately 1 atmosphere (about 16 pounds per square inch) will
force the glass more rapidly towards the center upon heating than what occurred for the ambient preparation
of the ampoule. Careful and broad heating will lead to success, whereas too hot of a flame focused on one
region may result in a hole in the tube and unsuccessful sealing under vacuum. Towards the end of the sealing,
the ampoule should be supported by one hand so that it doesn’t drop. The ampoule will be separated into two
45
portions. Place the bottom portion on a ring stand base to cool. If the top portion of the tube doesn’t seal, you
will hear this in the vacuum pump and see this on the vacuum gauge. If this occurs, seal and isolate the
manifold and turn off the vacuum gauge.
Hot glass and cold glass look identical. Allow the two portions of the tube to cool. The metal UltraTorr
connector and top portion of the ampoule will be hot after sealing. Wet paper towels wrapped around the
connector, along with air flow directed from a hose will aid in cooling. Seal off the main manifold from the
vacuum pump before loosening and removing the top portion of the tube from the metal UltraTorr connector
on the vacuum line. Retain and determine the mass of the top glass portion and the bottom ampoule containing
CuCl in a labeled (marker, include formula and initials) ampoule. Determine the mass of the CuCl in the
ampoule by difference and add the mass retained for magnetic susceptibility to determine the product yield.
Inspect the sealed ampoule one week later and check for discoloration that may have formed near any pin
holes formed during the sealing process.
References
(1) Engberg, A. An X-ray refinement of the crystal structure of copper(II) chloride
dihydrate. Acta Chemica Scandinavica 1970, 24, 3510-3526.
(2) Pfitzner, A. L., H.D. The systems Cu Cl-M(II)Cl 2 (M=Mn,Cd) - crystal structures of
Cu2MnCl4 and gamma-CuCl. Zeitschrift fuer Kristallographie 1993, 205 (2), 165-175.
(3) Hargittai, M.; Schwerdtfeger, P.; Réffy, B.; Brown, R. The Molecular Structure of
Different Species of Cuprous Chloride from Gas‐Phase Electron Diffraction and
Quantum Chemical Calculations. Chemistry – A European Journal 2003, 9 (1), 327-333.
(4) Hull, S.; Keen, D. A. High-pressure polymorphism of the copper(I) halides: A
neutron-diffraction study to ~10 GPa. Physical Review B 1994, 50 (9), 5868-5885.
(5) Jolly, W. L. The synthesis and characterization of inorganic compounds; PrenticeHall, Inc., 1970. Tanaka, J.; Suib, S. L. Experimental methods in inorganic chemistry;
Prentice-Hall, Inc., 1999.
46
Prelab: Synthesis of an air sensitive compound: copper(I) chloride
Clearly show work for credit.
1) Sketch the crystal field splitting diagram for an octahedral field.
2) Explain the term Jahn-Teller effect and indicate three d electron configurations that
exhibit this effect.
3) Sketch the crystal field splitting diagram for an axially elongated octahedral
environment and fill with the appropriate number of electrons from Cu 2+.
4) Sketch the crystal field splitting diagram for a tetrahedral environment and fill with the
appropriate number of electrons from Cu+.
47
Synthesis and characterization of a high
temperature superconductor: YBa2Cu3O7-x
Introduction:
In the early 1900’s, the Dutch physicist Heike Kammerlingh Onnes liquefied helium, a feat
that won him a Nobel Prize in 1913.1 The weak intermolecular forces in helium lead to a low boiling
point, 4.2 K, at atmospheric pressure. This discovery enabled the study of the properties of materials
at low temperature. In 1911 he found that mercury has zero electrical resistivity (superconductivity)
when cooled below 4 K. Other metallic elements also exhibiting superconductivity at low
temperature are shown in Fig. 1.
Fig. 1: Periodic table of superconducting elements at ambient pressure.
Meissner and Ochsenfeld, in 1933, found that in addition to the zero electrical resistivity, the
magnetic field inside a bulk specimen is zero. This expulsion of a magnetic field has been termed
the Meissner effect. Despite the appealing physical properties of zero electrical resistivity and
perfect diamagnetism, there are some drawbacks. The extremely cold temperatures necessary to
achieve superconductivity require liquid helium. The scarcity, high production costs, and complex
equipment needed to handle liquid helium are several obstacles to the implementation of these
superconductors into any new technologies. A second problem is that the superconducting states
of the elemental superconductors are easily destroyed by the application of moderate magnetic
fields or electrical currents. In order to overcome these drawbacks, intensive research began for
materials that were superconducting at higher temperatures and retained the superconducting state
in strong magnetic fields and large electrical currents. Certain alloys of niobium, for example
Nb3Ge, were found in 1973 to be superconducting at 23 K. Wire made from Nb3Ge or NbTi were
targets in the liquid helium cooled superconducting magnets of the CERN Large Hadron Collider. 2
Despite these advances and significant efforts, no superconductors have been found in metal alloys
that could be cooled with liquid nitrogen, an inexpensive cryogen.
48
Two scientists, Georg Bednorz and K. Alex Muller, while working at an IBM facility in Zurich
in 1986, reported an oxide BaxLa2-xCuO4 (x≈0.15) that was superconducting to near 35 K.3 For their
efforts, Bednorz and Muller received the Nobel Prize in Physics in 1987. 4 Previous oxides had been
discovered to be superconducting,5 but much of the scientific community held the idea that a
metallic oxide would not be superconducting at a ‘high’ temperature, meaning above the boiling
point of liquid nitrogen (77 K). Research by Paul Chu and M.K. Chu on oxides led to the synthesis
of YBa2Cu3O7–x (x≈0.25) and this compound remains superconducting to nearly 100 K, above the
boiling point of liquid nitrogen.6
The unexpected high temperature superconductivity led to reevaluation of the theories used to
describe superconductivity. There are several theories on superconductivities including the
phenomenological London Theory, the microscopic Bardeen-Cooper-Schrieffer (BCS) theory, and
the microscopic sudden polarization theory.7 Above the transition temperature, the sample is
paramagnetic and attracted into a magnetic field. Below the transition temperature, the sample
becomes strongly diamagnetic and is repelled by a magnetic field. If the applied magnetic field
exceeds a critical value, superconductivity is lost.
The YBa2Cu3O7–x (x ≤ 0.25) high temperature superconductor shows zero electrical resistance
and the Meissner effect at the superconducting temperature of ~95 K. The structure of YBa 2Cu3O7x may be described as a defect perovskite structure. Only about 7 of the 9 positions for the oxygen
atoms are occupied and the others are vacant. The crystal structure is shown in Fig. 2. A pure phase
of YBa2Cu3O7-x has the orthorhombic space group Pmmm with lattice parameters a = 3.82 Å, b =
3.89 Å, and c = 11.67Å.
Fig. 2. Crystal structure of the high Tc superconductor YBa2Cu3O7-x.
There are several synthetic methods available to prepare Y-123 superconductors, as these
YBa2Cu3O7-x compounds have come to be known. Solid state reaction, coprecipitation, and citrategel reactions have all been used. In this experiment, the conventional solid state technique will be
used.
49
Experimental:
Part 1: Synthesis of YBa2Cu3O7–x
Quantitatively weigh stoichiometric quantities 0.5084 g Y2O3, 1.7773 g BaCO3, and 1.0746 g
CuO. Obtain and record the mass of an alumina tray. The reactants may be used as received and do
not require drying. Mix and grind the reactants thoroughly for at least 10 minutes using a mortar or
pestle, preferably made from alumina or agate. Using weighing paper, extract the homogeneous
and finely ground powder from the mortar. Weigh a portion, (~1.5 g), and press a pellet using a
stainless steel die set (13 mm) to a reading of 800-1000 kg (~1 ton cm-2). Carefully extract the pellet
from the die and place it on a bed of ‘sacrificial powder’ of the same composition in a tray alumina
crucible. The sacrificial powder is used to prevent reaction of the pellet with the crucible. Place the
crucible near the center of a high temperature furnace.
Program the furnace to increase the temperature at 3 °C min-1 to 930 °C, dwell at this temperature
for 12 hours, cool at 3 °C min-1 to 500 °C and hold for several hours, then furnace cool to room
temperature. This heating cycle has been found to obtain samples with minimal secondary phases
and to provide optimized oxygen content in the superconducting sample.
Part 2: Meissner effect
Recover the sample and alumina tray from the furnace. Obtain the mass. Separate the pellet
from the sacrificial powder. Demonstration of the Meissner effect can be demonstrated by placing
the pellet on an upside down Styrofoam cup. Carefully pour liquid nitrogen to cool the pellet. Avoid
direct contact with liquid nitrogen, since it may cause frostbite. Using non-ferrous tweezers, place
(NdFeB) 1, 2, and 4 magnets on top of the pellet to observe the Meissner effect of the
superconducting sample. Obtain photos and a brief video. As the pellet warms above the
superconducting transition temperature, the magnets will cease to float.
Fig. 3. Meissner effect of a high Tc superconductor. Photo credit TJ Mullen.
The samples are not stable in moist air for an extended period of time. After warming to room
temperature, store the sample in a desiccator.
50
References
(1) Nobel Media, A. B. The Nobel Prize in Physics 1913.
https://www.nobelprize.org/prizes/physics/1913/summary/ (accessed 12/30/2021).
(2) CERN. SUPERCONDUCTIVITY AND CRYOGENICS FOR THE LARGE HADRON
COLLIDER. http://cds.cern.ch/record/473537/files/lhc-project-report-441.pdf (accessed
12/30/2021).
(3) Bednorz, J. G.; Müller, K. A. Possible high Tc superconductivity in the Ba−La−Cu−O
system. Zeitschrift für Physik B Condensed Matter 1986, 64 (2), 189-193.
(4) Nobel Media, A. B. The Nobel Prize in Physics 1987.
https://www.nobelprize.org/prizes/physics/1987/summary/ (accessed 12/30/2021).
(5) Sleight, A. W.; Gillson, J. L.; Bierstedt, P. E. High-Temperature Superconductivity in
BaPb1-xBixO3 System. Solid State Communications 1975, 17 (1), 27-28.
(6) Wu, M. K.; Ashburn, J. R.; Torng, C. J.; Hor, P. H.; Meng, R. L.; Gao, L.; Huang, Z.
J.; Wang, Y. Q.; Chu, C. W. Superconductivity at 93 K in a new mixed-phase Y-Ba-CuO compound system at ambient pressure. Physical Review Letters 1987, 58 (9), 908.
(7) Matsen, F. A. Three theories of superconductivity. Journal of Chemical Education
1987, 64 (10), 842-846.
51
Prelab: Synthesis and characterization of a high temperature superconductor:
YBa2Cu3O7-x
Clearly show work for credit. Use additional pages as needed.
1) Convert 77 K to °C.
2) The crystal structure of YBa2Cu3O6.73 adopts the orthorhombic space group Pmmm and
has one formula unit in the unit cell (Z = 1). Using Avogadro’s number, determine the
mass of one unit cell in grams.
3) The crystal structure of YBa2Cu3O6.73 adopts the orthorhombic space group Pmmm
with cell parameter a = 3.1893 Å, b = 3.8835 Å, and c = 11.6832 Å. Note 1 Å = 110-10
m. Determine the volume of the orthorhombic unit cell in cm 3.
4) Using the mass and volume of the unit cell above, calculate the theoretical density and
report to three significant figures.
5) Assuming a perfectly cylindrical pellet with mass = 1.3318 g, height = 3.67 mm, and
diameter 11.66 mm, determine the pellet density in g/cm 3.
6) Calculate the percent density by dividing the pellet density by the theoretical density,
then multiplying by 100.
52
Molarity of Concentrated Reagents
Typical* molarities of concentrated reagents utilized in the inorganic lab are shown
below.
Reagent
Acetic acid, CH3COOH
Ammonium hydroxide, NH4OH
Hydrochloric acid, HCl
Nitric acid, HNO3
*
Molarity (M)
17.5
15.4
12.2
15.8
For precise work, check the bottle label, since concentrations vary. HCl is available as
30%, 37%, or a range (e.g. 34% - 37%).
53
Filter Paper
Whatman Filter Paper Grades range from 1 to 6. Typically filter paper grades 1 and 3 are
available in the inorganic laboratory. A summary of grades 1 and 3 are given below.
Properties
Particle retention
(98% efficiency)
Thickness
(nominal)
Note:
Grade 1
11 μm
Grade 3
6 μm
180 μm
390 μm
Widely used filter paper in routine
applications requiring medium
retention and flow rate.
Thickness means it can hold more
precipitate without clogging and
has increased wet strength. Use in
Büchner funnels with large pores.
Adapted from:
https://www.cytivalifesciences.com/en/us/solutions/lab-filtration/knowledge-center/a-guide-to-whatman-filter-paper-grades
54
1.4 Instrumentation Instructions
55
Operating Instructions: Perkin Elmer FTIR Spectrum One
The Perkin-Elmer Spectrum One FTIR in 50/3508 measures the IR spectrum of solids. The
instrument/computer are usually left on. Log in to the PC with your UNF ID. Check the
spectrometer indicator panel to ensure the green lights are illuminated. Remove blue
cover/lid/protector if present. If the software is not already running, double click the Spectrum icon
on desktop. Login to the Spectrum software with the posted username and password that is listed
near the monitor.
Data Collection
Scan range is typically 4000 cm-1 to 650 cm-1. Accumulations depends on sample, generally 4
scans will be sufficient. Input Sample ID (e.g. 3initials_chemicalformula) and sample description.
With no sample, swing arm to place sleeve over detector, turn the knob clockwise to apply some
pressure, and use Background button to collect a background. Next, use a spatula to place a small
amount of sample (~1-2 mm3) above the measurement area, swing arm and to apply some pressure
to the sample. Click Scan.
Data processing and exporting
 Click Process, Peak list. Adjust thresholds if needed and reprocess from main view.
 The peak finding software will report to 0.01 cm-1. The data and data range should be reported
to the nearest cm-1 in lab reports.
 Save a PDF of the IR spectrum with labelled peaks for submission with the lab report. Upload
to cloud storage or copy to USB drive. Optional: print the spectrum, writing sample information
and chemical formula on the printed page.
 Loosen the pressure knob and swing arm away to storage position.
 Using a Kimwipe and alcohol, carefully clean stainless steel plate & bottom of metal sleeve.
 Ensure the entire area is clean and free of powder chemicals and supplies before leaving!
 The last user of the day should replace the blue cover/lid/protector and logout of Windows.
Troubleshooting
 If the Spectrum software won’t connect, another user may be using it in their user login. Restart
PC and try again. If it doesn’t connect after a restart, turn instrument off and then then back on.
 If the signal to noise is bad and peaks are not visible, the pressure on sample may be too low.
Increase pressure and collect data again.
 A spectrum with %T significantly above 100% typically indicates a bad background scan.
Clean the metal sleeve and detector area, recollect background and then the sample again.
*Optional, File – Report, to get details about data. File - Export Data for graphing, copy file into 1) e-mail or 2) USB
flash drive. Select three columns in list of peaks, copy and paste table into 1) e-mail or 2) flash drive. Prepare high-quality
figures for your lab report using Excel or comparable software.
56
Operating Instructions: Nicolet iS10 FTIR
The Nicolet iS10 FTIR in 50/3508 can measure the IR spectrum of solids. The instrument/computer
are usually left on. Login to the PC using your UNF login credentials. Double click the OMNIC
icon on desktop.
Background Spectrum
With no sample, click the
icon. It will display:
The collected background should be similar to:
In Add to Window, click no.
Sample Loading
Use a spatula to place a small amount of sample (~1-2 mm 3) above the measurement area. Do
not touch the spatula to the surface. Swing ATR upper screw handle/arm and to apply some pressure
to the sample until you hear one click.
57
Collecting the Spectrum of a Sample
Click the Col Smp
icon. Add brief title with sample information then click OK to collect.
The spectrum acquisition will occur. Click Yes to Add to Window.
Background subtraction
The background can be subtracted by clicking
, then click
to remove original spectrum.
Convert from Absorbance to % Transmittance
Click the Process menu, then % Transmittance (or Ctrl+T shortcut).
Data processing and finding peaks
Click Find Pks
.
If needed, adjust thresholds if needed by adjusting the threshold line. Click replace.
58
Manual adding of peaks can also be done. Click the “T” symbol in the bottom left, then click
the peak you want to add. Manual delete of a peak can be done by clicking the peak, then delete,
then press enter.
Printing and saving spectrum
You can edit the tile and sample information in the box above the spectrum.
Print the spectrum to a PDF file and obtain a copy (e.g. copy to cloud storage or USB drive).
Print a paper copy by printing to the Brother HL‐L8260CDW printed. Optional: save the spectrum
to TIFF (image) or CSV format (Excel) to create plot for use in laboratory report.
The peak finding routine in the software will report to 0.01 cm-1, but the data and data range is
typically reported to the nearest 1 cm-1. For example, a peak found at 1575.84 cm-1 would be
reported as 1576 cm-1.
59
Cleaning the ATR module
Loosen the pressure knob and swing arm to the side. Apply a isopropanol to a Kimwipe. Gently
and carefully clean ATR center and stainless steel plate and the bottom of the screw above.
Ensure the entire area is clean and free of powder chemicals and supplies before leaving! The
last user of the day should logout of Windows.
Troubleshooting
 Record issue/error message. Use print screen to capture error message and save to image or
paste into PowerPoint. E-mail to laboratory professor.
 If the software won’t connect, another user may be using it in their user login. Check for other
users in the Windows Task Manager. Find the person so they can login and close the software.
Otherwise restart the PC and try again. If it doesn’t connect after a restart, turn instrument off
and then then back on.
 A spectrum with %T significantly above 100% typically indicates a bad background scan.
Clean and dry the metal top sleeve and detector area, recollect background and then the sample
again.
 Any other issues see laboratory professor or Analytical Instrumentation Facility Manager
inside the Department of Chemistry office.
60
Operating Instructions: Perkin Elmer UV-Vis Lambda 35
The Perkin Elmer UV-Vis Lambda 35 in 50/3508 measures the UV-Vis spectrum of
solutions. Turn on green instrument switch with no cuvettes in the cuvette holders. Allow
the instrument to warm while you login to the PC with your n-number. Start UV WinLab
Explorer. Several methods will be available. Choose method titled “Inorganic Lab”.
Click Scan - Lambda35. Adjust data collection range as needed. Default is to collect data
from 300-700 nm, adjust to 326-800 nm unless otherwise noted. Slit width 1 nm, scan
speed 480 nm/min, interval 1 nm, change lamp at 325 nm.
61
Fill two plastic cuvettes about ¾ full with DI H2O and remove bubbles. Do not use plastic
cuvettes with acetone, ethanol, or any organic solvent. Data collection in non-aqueous
solutions requires glass or quartz cuvettes.
Note front on cuvette facing beam. Place in instrument cuvette holders. Perform Autozero
with the two cuvettes containing only DI H2O.
Collect data in range 326-800 nm or adjust range as needed.
Set samples to zero, then 1 to start new run. Type in Sample ID and description. Include
chemical formula, your name, concentration, and other pertinent information. Perform
Autozero with only DI H2O in the cuvettes.
62
Empty the front test cuvette and fill with prepared solution. Click start.
Insert cuvette, containing a solution of the sample of interest, into front cuvette holder in
the same orientation as before, while leaving DI H2O in rear cuvette holder.
Add peak labels via button, may need to shift threshold if too few or many peaks are found
with the peak search routine. Record the wavelength(s) of maximum absorbance and the
absorbance at these wavelength(s).
The figure below shows a UV-Vis spectrum of DI H2O. the plastic cuvette will absorb
strongly and provide unreliable data near 300 nm and lower wavelengths, whereas a glass
or quartz cuvette is transparent in this region. It may be necessary to adjust the y-axis
manually. Set minimum = 0 and set the maximum to slightly higher than the absorbance
of the peak(s) of interest.
Right click on the UV-Vis spectrum and print to the lab printer.
The last person to use the UV-Vis spectrophotometer should logoff and turn off the
instrument to prolong the lives of the two bulbs.
63
Operating Instructions: Hanna Instruments Conductivity Meter
The use of a Hanna Instruments conductivity meter enables the measurement of the
conductivity of solutions. Two electrodes are immersed in a solution and a potential is applied
between them, resulting in a current produced in the external circuit that connects the two
electrodes. The electrical communication between the two electrodes in solution involves the
movement of ions in the solution. Assuming no appreciable solution electrolysis occurs, the
magnitude of the current observed generally obeys Ohm’s Law: V = iR , where V is the applied
potential, i is the measured current, and R is the resistance of the solution. Electrical conductivity
(σ), the reciprocal of electrical resistivity (ρ), is a measure of a material’s ability to transfer, or
conduct, an electric current. The higher the concentration of ions present in the solution, the lower
the resistance (R) of a solution. More generally, resistance may be defined as:
l
in ohms
R
A
where ρ is the resistivity in ∙cm, l is the length in cm, and A is the cross section area in cm2. The
specific resistance is defined as the resistance in Ω (ohms) of a solution in an ideal cell that has 1
cm2 electrodes separated by a distance of 1 cm. The reciprocal of ρ is the specific conductance, L,
thus L = 1/ ρ. The specific conductance depends on the concentration of the electrolyte in the
solution. Typically, the conductivity will double if the concentration is doubled.
l
in Ω-1 cm-1 (or S/cm)
L
A R
The resistance, R, of the solution in a cell with nonstandard dimensions is obtained by
multiplying ρ by a cell geometry correction factor k. Experimentally, k may be evaluated by
measuring R for a given solution whose ρ has been measured in a standard cell and then calculating
k from the equation R = k ρ. For the purposes of these experiments, use a cell constant of 1.
The molar conductance, ΛM, is defined as the conductance of 1 cm3 cube of solution that
contains one mole (one formula weight) of solute. The specific conductance, L, is the conductance
of a 1 cm3 cube of solution and the conductance per mole of solute may be calculated by dividing
L by the number of moles present in 1 cm3 solution. Molarity is defined as moles/L and noting 1
mL is approximately 1 cm3, the molar conductivity can be expressed by:
1000 L
in S cm2/mol
M 
M
Typical molar conductivity are as follows for strong electrolytes:
Number of molar conductivity, Ω-1
ions
cm2 mol-1
2 (1:1)
96-150
3 (1:2)
225-273
4 (1:3)
380-435
5 (1:4)
540-560
Note different ions have different limiting ionic conductivities 20.
Ensure the glassware and probes are clean and rinsed with DI H2O. Measure the
conductivity of a solution by immersing the probe in a solution, ensuring the active
portions of the probe are covered. A graduated cylinder may be useful for low volume
solutions. Using the Hanna Instruments conductivity meter, the conductivity is
measured directly in mS/cm or μS/cm.
The accuracy of the conductivity probe may be checked by weighing 0.746 g of dry KCl and
dissolving in 1 L volumetric flask. The measured specific conductance should be near the
standard values listed in the following table.
Table 1: Specific conductance of a 0.010 M KCl solution.
64
Temperature (°C) Specific conductance, S/cm
15
0.001147
16
0.001173
17
0.001199
18
0.001225
19
0.001251
20
0.001278
21
0.001305
22
0.001332
23
0.001359
24
0.001386
25
0.001413
26
0.001441
27
0.001468
28
0.001496
If the values are substantially different, rinse the conductivity meter with DI water and measure
again.
Rinse the probe and ensure the equipment is clean and free of chemicals before returning to
the storage box.
Sample calculation with representative student data:
A 25.00 mL solution of [Co(H2O)6](NO3)2 was prepared with a concentration 0.00500 M. The
conductance (SI units, S m-1) of the solution was measured and found to be 950 μS/cm. The
conductance is therefore 9.50×10-4 S/cm. The molar conductivity (SI units, S cm2 mol-1) is
normalized for the concentration and is calculated as follows:
1000 L
M 
M
More explicitly,
Λ
=
( .
( .
×
/
/
)
)
=
( .
( .
×
/
Λ
/
)(
)
/
)
=
(
)( .
( .
×
/
)
)
= 190 S cm mol
There are three ions expected in solution, [Co(H2O)6](NO3)2  [Co(H2O)6]2+(aq) + 2 NO3- (aq)
For this example, the charge of the ion is not considered. The value is slightly less than the
expected 225-273 S cm2 mol-1 given in the table of typical molar conductance values for various
ion conductors with three ions in solution. A possible reason may be that large, heavy ions are
less mobile and this results in a slightly lower molar conductivity value.
References
[1] L. Coury, Conductance Measurements Part 1: Theory, Current Separations 18(3) (1999) 9196.
65
Optical Polarimetry
In a typical polarimetry experiment, monochromatic light is passed through the sample. A
sodium lamp is usually used as the light source and the wavelength of its D line is 589.3 nm.
The light provided by the source is not polarized so its electromagnetic waves oscillate in all
planes perpendicular to the transverse axis. After passing through a polarizing lens (prism), the
only light remaining is oscillating in one plane (plane polarized), whose angle is determined
by the angle of the lens itself. This light is then passed through a solution of an optically active
compound, which results in a rotation of the plane of oscillation. A second polarizing lens
(prism) is used in conjunction with a detector to find the angle of rotation.
The magnitude of the rotation is not only determined by the intrinsic properties of the
molecule, but also on the concentration, path length, and wavelength of light. These parameters
should be familiar from use of a UV/Vis spectrometer. To standardize the optical rotations
reported in the literature, a parameter has been defined as the specific rotation [α]λ:
The parameters are
α
the rotation measured by the polarimeter in degrees
meas
λ the wavelength used to measure the rotation in nanometers
l the path length in decimeters (typically this is 1 or 2 dm, note that 1 dm = 0.1 m or 10 cm)
c the concentration in g/mL
Normally [α]λ values are quoted in the literature at a specific temperature (e.g. 15 or 20 ºC).
There is a slight temperature dependence on optical rotation, which can be corrected using:
[α]λ(15 ºC) = [α]λ(T) [1 + 0.0001(T - 15)]
The percent optical purity (x) of a material is the ratio of the measured specific rotation,
[α]λ(meas), to the standard pure specific rotation, [α]λ(std), where x = [α]λ(meas)/[α]λ(std) *100. The
percentage of the major enantiomer in a mixture of enantiomers can be calculated as:
% (major enantiomer) = x + (100 -x)/2
Thus, if a sample is an equal mixture of (+) and (-) enantiomers, the measured rotation is zero
and x = 0, so the % (major enantiomer) = 50 %.
66
Instrument overview and polarimeter tube preparation
Data collection using a polarimeter may be conducted using a manually operated
Polyscience SR-6 polarimeter and/or a computer controlled polarimeter in the Physical
Chemistry laboratory. The SR-6 and polarimeter tube is shown below.
Polarimeter tubes are available in different lengths (e.g. 1 or 2 dm). Confirm the length of
polarimeter using a ruler. Fill the tube completely with the solution of interest and avoid the
creation of air bubbles. When the tube is filled to the top, slide a clean and dry glass cover disc
from the side of the tube across the opening. Place the cover cap on and tighten securely to
avoid leaks, but don’t overtighten. Prepare a secondary tube filled with DI H2O for a
demonstration. Ensure the outside of the tube(s) is/are dry.
Measuring Procedure
Turn on the lamp for the instrument. Insert the tube containing DI H2O with the broader
end up. Rotate the light shield over the measuring chamber.
1. Rotate the vernier so that the zero (0) is at the zero (0) of the circular scale.
2. Adjust the magnifying lens of the measuring field so that the dividing line between the half
circles is in focus. The half shadows should appear in equal brightness.
3. If the darker half shadow is to the right, then the solution contains a substance that is
dextrorotatory (rotates the light beam to the right). A darker left shadow indicates a
levorotatory substance (rotates the light beam to the left).
4. Turn the vernier in the same direction as the rotation until both half shadows appear in
equal brightness. The degree of rotation is then read off the circular scale. Multiple
measurements can made to obtain a mean value.
5. Look into the scale reader for degree reading. Line up the vernier zero (0) to the upper scale
and note the reading to the nearest degree for a more precise reading, the vernier will
indicate tenths of degrees.
67
Measuring Procedure on computer controlled instrument
Log into instrument and open polarimeter control software. Pour DI H2O into graduated
cylinder and record the height (path length l) in dm. Place under apparatus. Record
measurement of DI H2O by initiating run and rotating clockwise. Fit peak using software and
record peak position. Discard water and then pour sample into graduated cylinder and record
the height (path length) in dm. Place under apparatus. Record measurement of solution by
initiating run and rotating clockwise. Fit peak using software and record peak position.
Determine the rotation angle by difference.
Example calculation
A 5.1137 g sample of diammonium tartrate was dissolved and dilute to 25.00 mL in a
volumetric flask. The solution was placed in a 2 dm polarimeter tube. The ambient
temperature was 23 °C. The observed rotation angle was 13.8°.
c = 5.1137 g/25.00 mL = 0.2045 g/mL
optical activity (°), calculated [α] = 13.8/(20.2045) = 33.73°
Corrected, optical activity (deg) = 33.73°(1 + 0.0001(23 - 20)] = 33.76°
Literature value (https://pubchem.ncbi.nlm.nih.gov/compound/Diammonium-tartrate#section=Stability-Shelf-Life), 34.6°
Calculate the percent error, [(33.73°-34.6°)/34.6°]100 = -2.4%
68
Magnetic susceptibility of transition metal containing compounds
Introduction:
Measurements of magnetic properties have been used to characterize a wide range of
systems from oxygen, metallic alloys, solid state materials, and coordination complexes
containing metals. Most organic and main group element compounds have all the electrons
paired and these are diamagnetic molecules with very small magnetic moments. All
transition metals have at least one oxidation state with an incomplete d subshell. Magnetic
measurements, particularly for the first row transition elements, give information about the
number of unpaired electrons. The number of unpaired electrons provides information
about the oxidation state and electron configuration. The determination of the magnetic
properties of the second and third row transition elements is more complex.
The magnetic moment is calculated from the magnetic susceptibility, since the
magnetic moment is not measured directly. There are several ways to express the degree
to which a material acquires a magnetic moment in a field. The magnetic susceptibility per
unit volume is defined by:
𝐼
𝐻
where I is the intensity of the magnetization induced in the sample by the external magnetic
field, H. The extent of the magnetic induction (I) depends on the sample. The induction
may be visualized as an alignment of dipoles and/or by the formation of charge polarization
in the sample. H is the strength of the external magnetic field in units of oersteds (Oe). The
κ is unitless.
Generally, it is more convenient to use mass units, therefore the mass or gram
susceptibility is defined as:
𝜅
𝜒 =
𝑑
where d is the density of the solid. The molar susceptibility is the mass susceptibility
multiplied by the formula weight.
𝜅=
𝜒 = 𝜒 (𝐹. 𝑊. 𝑖𝑛 𝑔 𝑚𝑜𝑙
)
The terms κ, χg, and χm are all measures of the magnetic moment of a substance in a
magnetic field.
Relating susceptibility to unpaired electrons:
The relationship between the applied magnetic field and the moments resulting in the
diamagnetic and paramagnetic susceptibilities, combined with the contribution for other
effects including Van Vleck paramagnetism, can be described in terms of the effective
magnetic moment eff, where k = Boltzmann’s constant, T = absolute temperature,  =
Bohr Magneton, N is Avogadro’s number, and 'A is the susceptibility per gram of the
paramagnetic ion.
𝜇
=
= 2.84 𝜒 𝑇 in units of B.M.
The units are in B.M. (Bohr Magnetons), which is a unit of magnetic moment and equal to
eh/4πmc = 9.27×10-21 erg/gauss. The a is the atomic susceptibility corrected for the
69
diamagnetic components of the ligands and associated ions. The diamagnetic corrections
for cations, anions, and individual atoms and are given in units of ×10-6 erg*G-2 mol-1.
Table 1 (left) Diamagnetic corrections and (right) Pascal’s constants,×10-6 erg*G-2 mol-1.
Cations
Anions
Molecules
Pascal’s Constants
Li+
1.0
F9.1
H2O 13
H
Na+
6.8
Cl23.4 NH3 16
C
K+
14.9 Br34.6 en
47
N (ring)
Rb+
22.5 I50.6 py
49
N (open chain)
+
N (mono amide)
Cs
35.0 CH3CO2 29
PPh3 167
+
N (diamide imide)
Tl
35.7 C6H5CO2 71
O (ether alcohol)
NH4+
13.3 CN13
O (ketone aldehyde)
Hg2+
38
CNO23
O (carboxyl)
Mg2+
5
CNS34
F
Cl
Zn2+
15
ClO434
2+
2Br
Pb
32
CO3
28
I
2+
2Ca
10.4 C2O4
28
S
Sr2+
16
HCO217
Sr
Ba2+
26
NO319
Te
P
Fe2+
12.8 O26
2+
As(V)
Cu
12.8 OH
11
As(III)
2+
-2
Co
12.8 S
28
Sb(III)
Ni2+
12.8 SO4-2
38
Li
Cu1+
15
S2O3246
Na
K
Ag1+
27
acac55
2+
Si
Cd
20
Pb
Other
13
Sb(IV)
First Row
Mg
Transition
Ca
Metals
Al
Zn
Hg(II)
Measurement of magnetic susceptibility:
The Guoy method, Faraday method, and determination of magnetic susceptibility by
nuclear magnetic resonance (NMR) are all experimental techniques to determine the
magnetic susceptibility of transition metal containing coordination compounds. The Evans
balance, developed by Professor D.F. Evans of Imperial College London, is a compact and
self-contained experimental apparatus. The digital readout provides rapid and accurate
readings and the sensitivity rivals that of traditional methods. The instrument also has the
advantage that samples as small as 50 mg may be measured.
The Evans balance has the same basic configuration as found in the Guoy method. The
sample is suspended between two poles of a magnet. The balance measures the apparent
change in the mass of the sample. The sample is repelled or attracted to the magnetic field
for diamagnetic and paramagnetic substances, respectively. The Evans balance doesn’t
70
2.93
6.00
4.61
5.57
1.54
2.11
4.61
-1.73
3.36
6.3
20.1
30.6
44.6
15.0
23
37.3
26.3
43.0
20.9
74.0
4.2
9.2
18.5
20
46
30
10.0
15.9
13
13.5
33
measure mass directly or the force the magnet exerts on the sample. It measures the force
the stationary sample exerts on the suspended permanent magnets, which is accomplished
by measuring the change in current required to keep a set of permanent magnets in balance
after the magnetic fields interact with the sample. The two pairs of magnets are located on
one end of a balance beam. When the sample is placed between the poles of one pair of
magnets, the beam is deflected and changes position. The change is detected by a coil or
photodiode on opposite side of the equilibrium position of the balance beam. A current is
passed through a coil to exactly cancel the interaction force. The current needed is
proportional to the force exerted by the sample and is used to measure the magnetic
susceptibility. The current is measured with a digital voltmeter connected across a precision
resistor, in series with the coil, and displayed on the digital display.
The general mass magnetic susceptibility, χg, using an Evans balance is:
𝐿
𝜒 = {𝐶(𝑅 − 𝑅 + 𝜒 𝐴}
𝑚
L = sample height in centimeters
m = sample mass in grams
C = balance calibration constant (typically near 1.00x)
R = reading from the digital display when the sample and tube is in place in the instrument
R0 = reading from the digital display when the empty sample tube is in the instrument
v’ = volume susceptibility of air (0.029 × 10-6 erg G-2 cm-3)
A = cross-sectional area of the sample
Calibration of the Evans balance is typically done with Hg[Co(SCN) 4] or [Ni(en)3]S2O3,
which have values of 1.644 × 10-5 erg G-2 cm-3 and 1.104 × 10-5 erg•G-2 cm-3, respectively.
The volume susceptibility contribution from air is relatively small and can usually be
neglected for the measurement of the magnetic susceptibility of solid samples.
The mass magnetic susceptibility can be rewritten as:
𝜒 = 𝐶𝐿(𝑅 − 𝑅 )/[(1 × 10 )(𝑚)]
and has units of erg•G-2 g-1. Use this equation to calculate the χg.
The molar susceptibility, χm, is calculated by multiplying the mass magnetic susceptibility
by the formula weight:
𝜒 = 𝜒 (𝐹. 𝑊. 𝑖𝑛 𝑔 𝑚𝑜𝑙 )
and has c.g.s. units of erg•G-2 mol-1. A negative molar susceptibility indicates
diamagnetism.
Diamagnetic corrections to the molar susceptibility are made to account for the inner core
electrons, ligands, atoms, and ions in the compound or material, which make the apparent
molar susceptibility smaller than it really is from the contribution from the unpaired
electrons. The diamagnetic contributions are added to the value of χ m to obtain the χA, the
molar susceptibility of the paramagnetic atom. Select diamagnetic corrections are given in
table 1 and more extensive tables are found in the literature 1, 21. The diamagnetic correction
71
for ligands or other groups not found in the table can be obtained by summing the Pascal’s
constants for each atom or type of atom in the group as found in the table 1 or primary
literature. The corrections tend to be small, as the unit of the corrections is in ×10-6 erg*G2
mol-1.
𝜒 = 𝜒 + sum of diamagnetic corrections
The corrected molar magnetic susceptibility, χA, can be related to the effective magnetic
moment in Bohr Magnetons by:
3𝑘𝑇𝜒 /
𝜇
=
𝑁𝛽
where k is the Boltzmann constant, N is Avogadro’s number, and  is the Bohr magneton.
Thus, the equation simplifies to:
𝜇
= 2.828(𝜒 𝑇) /
The measured eff can be compared to the calculated value, s, from the spin-only formula,
where the orbital angular momentum is assumed to be quenched by the ligand field.
𝜇 = 𝑔 𝑆(𝑆 + 1)
where S is the total spin of the paramagnetic center with n unpaired electrons.
n
1
2
3
4
5
s (B.M.)
1.73
2.83
3.87
4.90
5.92
The measured value of eff varies slightly from one compound or material to another, as
shown in tables 2 and 3 for transition metals in an octahedral and tetrahedral geometry,
respectively. For some configurations, there is an orbital contribution to the magnetic
moment. The number of unpaired electrons for other coordination geometries can be
predicted by considering the splitting of the d-orbitals, and crystal field stabilization energy
22
.
72
Table 2 Measured magnetic moments, d-configuration, and number of unpaired electrons
for transition metal ions with an octahedral geometry.
Metal Ion
Ti4+, V5+
Ti3+, V4+
V3+
Cr3+, Mn4+
Cr2+, Mn3+
Fe3+, Mn2+
Fe2+, Co3+
Co2+
Ni2+
Cu2+
Cu+
d configuration Number
of
Unpaired Electrons
d0
0
d1
1
2
d
2
d3
3
4
d
4 (high spin)
2 (low spin)
5
d
5 (high spin)
1 (low spin)
d6
4 (high spin)
0 (low spin)
d7
3 (high spin)
1 (low spin)
d8
2
9
d
1
d10
0
Magnetic
(B.M.)
0
1.7-1.8
2.7-2.9
3.7-3.9
4.8-5.0
3.0-3.3
5.7-6.0
2.0-2.5
5.6-5.9
0
4.3-5.2
2.0-2.7
2.9-3.3
1.8-2.1
0
moment
Table 3 Measured magnetic moments, d-configuration, and number of unpaired electrons
for transition metal ions with a tetrahedral geometry.
Metal Ion
Ti4+, V5+
Cr5+
Cr4+
Fe5+
Mn2+
Fe2+
Co2+
Ni2+
Cu2+
Cu+
d configuration Number
of
Unpaired Electrons
d0
0
1
d
1
d2
2
3
d
3
4
d
d5
5 (high spin)
6
d
4 (high spin)
d7
3 (high spin)
8
d
2
d9
1
10
d
0
Magnetic
(B.M.)
0
1.7-1.8
2.6-2.8
3.6-3.7
5.9-6.2
5.3-5.5
4.2-4.8
3.7-4.0
0
moment
Treatment of spin and orbital contributions to the magnetic moment are treated in section
20.10 of Housecroft and Sharpe 22.
73
Instructions for operation of the Evans Balance by Johnson Matthey:
1. Place the balance on a flat surface and level using the bubble. Plug in/turn on. Note:
the balance is sensitive to breakage and should not be moved.
2. Turn the RANGE dial to ×1 and allow the balance to warm up for 5-10 minutes.
3. Adjust the ZERO dial until the display reads 000. The zero should be readjusted if the
range is changed. Note: The zero dial has a range of about 5 turns and works best in
in the middle of the range. If needed, adjust the dial 5 turns from one end and adjust
the back legs of the balance until the display reads near zero. All further adjustments
should be done from the front of the Evans balance.
4. Measure the R reading of the sealed tube standard. The R and R0 are on the tag (e.g. R
= 1174).
5. Weigh an empty tube and place into the tube guide. Record the reading R0. The
instrument can drift over time, therefore it should be rezeroed before each
measurement. The digital display should fluctuate by no more than ±1 on the ×1 setting.
Note a range of readings if there is significant fluctuation.
6. Fill the sample tube with the sample of interest. Gently tap the bottom of the tube on a
hard surface to increase the packing density. The height of the sample in the tube should
be at least 1.5 cm, ideally between 2.50 and 3.50 cm. Measure and record the mass of
the tube and sample using an analytical balance. Measure the height of the level sample
contained in the tube.
7. Rezero the empty balance and place the tube containing the sample into the tube guide.
Record the reading R.
a. If the reading of off-scale, adjust the RANGE dial to ×10, rezero, and take an
additional reading and multiply the reading by 10.
8. Gently tap the tube containing the sample on a hard surface again to further pack the
sample, and then take another reading of R. Repeat until several readings are within
±1.
9. Determine the temperature (T) to 0.1 °C with a thermometer clamped near the balance.
10. The sample may be removed from the tube by gently tapping the tube upside down on
a piece of weighing paper. Avoid chipping or breaking the glass lip on the tube. The
tubes are >$50 each.
11. After removing most of the cotton from a cotton swab, scrub the inside of the tube to
remove any remaining loose powder.
12. Rinse the empty tube with ethanol and then acetone with a fine-tip disposable pipette,
drying between each step. Ensure the tube is dry before using again.
13. Calculate Cbal = [R(label) of standard]/[R(measured) of standard], (typically 1.00x)
14. Tabulate the data R, Ro, L, M, and T with proper units and significant figures.
15. Calculate the eff and compare to typical range for dn configuration listed in Tables 2
and 3. Consider more advanced treatments with orbital contributions if the results are
in poor agreement with predictions.
74
References
(1) Angelici, R. J. Synthesis and technique in inorganic chemistry; W.B. Saunders, 1977.
(2) Szafran, Z.; Pike, R. M.; Singh, M. M. Microscale Inorganic Chemistry; John Wiley
and Sons, Inc., 1991. Schlessinger, G. G. Inorganic laboratory preparations; Chemical
Publishing Company, Inc., 1962. Walton, H. F. Inorganic Preparations; Prentice-Hall,
Inc., 1948.
(3) Schlessinger, G. Carbonatotetramminecobalt(III) Nitrate. In Inorganic Syntheses,
McGraw‐Hill Book Company, Inc., 1960; pp 173-175. Dixon, N. E.; Jackson, W. G.;
Lawrance, G. A.; Sargeson, A. M. Cobalt(III) amine complexes with coordinated
trifluoromethanesulfonate. In Inorganic Syntheses, Holt, S. L. Ed.; Wiley-Interscience,
1983; p 103. Richens, D. T.; Glidewell, C. Linkage isomerism: an infra-red study. In
Inorganic Experiments, Woollins, J. D. Ed.; Vol. 2; Wiley-VCH, 2003.
(4) Tanaka, J.; Suib, S. L. Experimental methods in inorganic chemistry; Prentice-Hall,
Inc., 1999. Jolly, W. L. The synthesis and characterization of inorganic compounds;
Prentice-Hall, Inc., 1970.
(5) Housecroft, C. E.; Sharpe, A. G. Inorganic Chemistry; Pearson Education Limited,
2018.
(6) Bernal, I.; Cetrullo, J. The phenomenon of conglomerate crystallization. XVIII.
Clavic dissymmetry in coordination compounds. XVI. Structural Chemistry 1990, 1 (2),
227-234. DOI: 10.1007/BF00674266. Junk, P. C.; Steed, J. W. Syntheses and X-ray
crystal structures of [Co(η2-CO3)(NH3)4](NO3)·0.5H2O and [(NH3)3Co(μ-OH)2(μCO3)Co(NH3)3][NO3]2·H2O. Polyhedron 1999, 18 (27), 3593-3597. DOI:
https://doi.org/10.1016/S0277-5387(99)00293-4. Christensen, N. H., R. G. X-Ray
Crystallographic Study and Thermogravimetric Analysis of TetrammineCarbonatocobalt(III) Nitrate Hemihydrate, [Co(NH3)4CO3]NO3.0.5H2O. Acta Chemica
Scandinavica 1999, 53, 399-402.
(7) Talebi, S.; Amani, V.; Saber-Tehrani, M.; Abedi, A. Improvement of the Biological
Activity of a New Cobalt(III) Complex through Loading into a Nanocarrier, and the
Characterization Thereof. ChemistrySelect 2019, 4 (45), 13235-13240. DOI:
https://doi.org/10.1002/slct.201903065.
(8) Chen, Y.; Christensen, D. H.; Faurskov Nielsen, O.; Pedersen, E. NIR-FT-Raman
spectra of some cobalt(III) ammine complexes. Journal of Molecular Structure 1993,
294, 215-218. DOI: https://doi.org/10.1016/0022-2860(93)80353-W.
(9) Girolami, G. S.; Rauchfuss, T. B.; Angelici, R. J. Synthesis and technique in
inorganic chemistry: a laboratory manual; University Science Books, 1999.
(10) Penland, R. B.; Lane, T. J.; Quagliano, J. V. Infrared Absorption Spectra of
Inorganic Coordination Complexes. VII. Structural Isomerism of Nitro- and
Nitritopentamminecobalt(III) Chlorides. Journal of the American Chemical Society 1956,
78 (5), 887-889. DOI: - 10.1021/ja01586a001.
(11) Basolo, F.; Hammaker, G. S. Synthesis and Isomerization of Nitritopentammine
Complexes of Rhodium(III), Iridium(III), and Platinum(IV). Inorganic Chemistry 1962, 1
(1), 1-5.
(12) Pinho, S. P.; Macedo, E. A. Solubility of NaCl, NaBr, and KCl in Water, Methanol,
Ethanol, and Their Mixed Solvents. Journal of Chemical & Engineering Data 2005, 50
(1), 29-32. DOI: - 10.1021/je049922y.
75
(13) Thompson, D. W.; Ito, A.; Meyer, T. J. [Ru(bpy) 3]2+* and other remarkable metal-toligand charge transfer (MLCT) excited states. Pure and Applied Chemistry 2013, 85 (7),
1257-1305. DOI: doi:10.1351/PAC-CON-13-03-04.
(14) Marmon, J.; Lisensky, G.; deProphetis, W. Preparation of an Organic Light
Emitting Diode. https://chem.beloit.edu/edetc/nanolab/oLED/index.html (accessed 2021
Web Page).
(15) Müller, S.; Rudmann, H.; Rubner, M. F.; Sevian, H. Using Organic Light-Emitting
Electrochemical Thin-Film Devices To Teach Materials Science. Journal of Chemical
Education 2004, 81 (11), 1620. DOI: 10.1021/ed081p1620; M3: doi:
10.1021/ed081p1620; 24
10.1021/ed081p1620 (acccessed 11/01; 2013/01).
(16) Engberg, A. An X-ray refinement of the crystal structure of copper(II) chloride
dihydrate. Acta Chemica Scandinavica 1970, 24, 3510-3526.
(17) Pfitzner, A. L., H.D. The systems Cu Cl-M(II)Cl 2 (M=Mn,Cd) - crystal structures of
Cu2MnCl4 and gamma-CuCl. Zeitschrift fuer Kristallographie 1993, 205 (2), 165-175.
(18) Hargittai, M.; Schwerdtfeger, P.; Réffy, B.; Brown, R. The Molecular Structure of
Different Species of Cuprous Chloride from Gas‐Phase Electron Diffraction and
Quantum Chemical Calculations. Chemistry – A European Journal 2003, 9 (1), 327-333.
DOI: doi:10.1002/chem.200390027.
(19) Hull, S.; Keen, D. A. High-pressure polymorphism of the copper(I) halides: A
neutron-diffraction study to ~10 GPa. Physical Review B 1994, 50 (9), 5868-5885.
(20) Coury, L. Conductance Measurements Part 1: Theory. Current Separations 1999, 18
(3), 91-96.
(21) Figgis, B. N.; Lewis, J. In Modern Coordination Chemistry, Lewis, J., Wilkins, R.
G. Eds.; Interscience Publishers Inc., 1960; pp 400-454.
(22) Housecroft, C. E.; Sharpe, A. G. Inorganic Chemistry; Pearson Education Limited,
2012.
Sample calculation: magnetic susceptibility
An Evans balance showed a R = 1168 for a standard with R = 1174. The temperature
of the laboratory near the balance was 19.9 °C. A magnetic susceptibility tube with inside
diameter 0.317 cm has measured Ro value of 27. A sample of iron(III)chloride
hexahydrate was added to the tube to a length of 3.20 cm. The mass of the
iron(III)chloride hexahydrate was 0.2602 g. The sample tube was introduced to the
zeroed Evans balance set to the x1 scale. The reading was off the scale, so the adjustment
was set to x10 and a reading of 402 was obtained, resulting in an adjusted R reading of
4020. The measurement was repeated using the same tube and an average R reading was
4020.
Cbal = 1174/1168 = 1.005
Calculate the molar mass of FeCl3·6H2O, 270.29 g/mol. The mass susceptibility (χg)
is calculated as follows:
𝜒 = 𝐶𝐿(𝑅 − 𝑅 )/[(1 × 10 )(𝑚)]
𝜒 =
( .
)( . )(
[( ×
)( .
)
)]
= 5.00 × 10
76
erg•G-2 g-1
Molar magnetic susceptibility (χm):
𝜒 = (5.00×10-5 erg•G-2g-1)(270.29 g/mol) = 1.35×10-2 erg•G-2mol-1
The diamagnetic corrections (given in ×10-6 erg*G-2 mol-1) are made for the three
chloride ions and six water molecules in the formula.
(23.4×10-6 erg*G-2 mol-1)(3)+(13×10-6 erg*G-2 mol-1)(6) = 1.48×10-4 erg*G-2 mol-1
Calculate the corrected χa by adding the correction to the molar magnetic susceptibility.
χa = 1.35×10-2 erg•G-2mol-1 + 1.48×10-4 erg*G-2 mol-1 =1.37×10-2 erg•G-2mol-1
Convert temperature from °C to K, 19.9 °C + 273.15 = 293.25 K.
Calculate the effective magnetic moment, eff.
𝜇
= 2.828(𝜒 𝑇) / = 2.828 (1.37 × 10 × 293.25) = 5.66 B. M.
Fe3+ is a d5 ion with the possibility for high spin and low spin configurations in an
octahedral geometry. The spin only formula predicts s = 5.92 B.M. and 1.73 B.M. for
high spin and low spin, respectively. Table 2 lists a typical range 5.7-6.0 B.M. for five
unpaired electrons (high spin) octahedral d 5 ions and the low spin d5 configuration has
one unpaired electron has a typical range 1.7-1.8 B.M..
This measured effective magnetic moment is consistent with high spin iron with five
unpaired electrons, which is also consistent with the weak field ligands surrounding iron
(water) in this compound.
77
6 Guidelines for preparing reports
Organization of the Research Report
Scientific research reports, irrespective of the field, utilize the method of scientific reasoning. The
problem is defined as clearly as possible, a hypothesis is created, experiments are devised to test
the hypothesis, experiments are conducted, data is analyzed, and conclusions are drawn. A typical
report is organized as follows:







Title (with authors and affiliation)
Abstract
Introduction
Experimental
Results and Discussion
Conclusions
References
Title and Title Page
The title should reflect the scientific of the project described in the report. It should be as succinct
as possible and include essential key words.
The author's name should follow the title on a separate line, followed by the author's affiliation
(e.g., Department of Chemistry, University of North Florida, Jacksonville, FL), and the date.
All of the above may appear on a single cover page.
Abstract
The abstract should, in the briefest terms possible, describe the topic, the scope, the principal
findings, and the conclusions. Generally it should be written last to accurately describe the content
of the report. The lengths of abstracts vary, but seldom exceed one paragraph.
A primary objective of an abstract is to communicate to the reader the core of the report. The reader
will then be the judge of whether to read the full report.
Introduction
"A good introduction is a clear statement of the problem or project and why you are studying it."
(Dodd, J. S., Ed. The ACS Style Guide; 2nd, American Chemical Society: Washington, DC, 1997,
pg 20).
The opening paragraphs should illustrate the nature of the problem and why it is of interest. This
section should describe clearly and briefly the background information on the problem, what has
been done before (with proper literature citations), and the objectives of the current project. A clear
association between the current experiment and the scope and limitations of earlier work should be
made so that the reasons for the experiment and the approach used will be understood.
78
Experimental
This section should describe what was actually done in the laboratory. It is a short description of
the laboratory notebook. The procedures, chemicals and manufacturers, techniques,
instrumentation, and special precautions are described to give an experienced reader sufficient
information to repeat the work and obtain comparable results. The model and names of the
instrument manufacturer and the specific scan conditions should be included.
If the experimental section is lengthy and detailed, as in some synthetic work, it can be placed at
the end of the report or as an appendix so that it does not interrupt the conceptual flow of the report.
The placement will depend on the nature of the project and the discretion of the writer. The current
literature is a good place to view example experimental sections.
Results and Discussion
In the results section the relevant data, observations, and findings are summarized. Tabulation of
data, equations, charts, and figures can be used effectively to present results clearly and concisely.
Schemes to show reaction sequences may be used here or elsewhere in the report.
The crux of the report is the analysis and interpretation of the results. What do the results mean?
How do they relate to the objectives of the project? To what extent have they resolved the problem
presented in the introduction?
The "Results" and "Discussion" sections are interrelated and can and are often combined as one
“Results and Discussion” section.
Conclusions
A separate section outlining the main conclusions of the project is appropriate if conclusions have
not already been stated in the 'Results and Discussion' section. Directions for future work or
modifications to the procedure, where appropriate, may also be expressed in the conclusions.
The last paragraph of text in manuscripts prepared for publication is customarily dedicated to
acknowledgments. However, there is no rule about this, and research reports or senior theses
frequently place acknowledgments as a separate section.
References
Literature references should be listed at the end of the report and cited in one of the formats (e.g.
numbered) described in The ACS Style Guide or standard journals. Do not mix formats. All
references should be checked against the original primary literature, not merely websites. Never
cite a reference that you have not read yourself. Double check all journal year, volume, issue, and
inclusive page numbers to ensure the accuracy of your citation. The recommended format is found
in the Inorganic Chemistry journal published by the American Chemical Society.
Acknowledgments
Thank staff, faculty, and students who assisted with data collection, analysis, or experimental
issues.
Supporting Information
Include trivial calculations, figures, and any data that does not appear in the manuscript text.
79
Preparing the Report
The personal computer and word processing software have made manuscript preparation and
revision a great deal easier than it used to be. Students should have the opportunity to use a word
processor and have access to software (e.g. Excel) that allows numerical data to be graphed,
chemical structures to be drawn, and mathematical equations to be represented. UNF offers a
variety of resources (e.g. SciFinder Scholar). These are essential tools of the technical writer. All
manuscripts should routinely be checked for spelling and all paper should be carefully proofread
before being submitted for a grade.
Your report should be written in your own words and follow appropriate citation style for any facts
cited. In this laboratory course, use the ACS reference style guidelines
(https://guides.lib.berkeley.edu/chem/citations). You may find it practical to use RefWorks
(https://www.refworks.com/) or EndNote to handle the bibliography. There is a learning curve, but
you will find it useful and it will save you time in the long term.
An electronic copy of the laboratory report must be submitted on Canvas. Any source referenced
in the report must be presented upon request.
References
Alley, M. The Craft of Scientific Writing; Prentice-Hall: Englewood Cliffs, NJ, 1987.
Cain, B. E. The Basics of Technical Communicating; ACS Professional Reference Book,
American Chemical Society: Washington; DC. 1988.
Dodd, J. S., Ed. The ACS Style Guide; American Chemical Society: Washington, DC, 1997.
Ebel, H.F.; Bliefert, C.; Russey, W.E. The Art of Scientific Writing, Wiley VCH, 2004.
Kanare, H. M. Writing the Laboratory Notebook; American Chemical Society: Washington, DC,
1985.
Macrina, FL. Scientific Integrity, 2nd edition (2005)
O’Conner, P. T. Woe is I: The Grammarphobe’s Guide to Better English in Plain English; G. P.
Putnam’s Sons: New York, 1996.
Plotnik, A. The Elements of Editing: A Modern Guide for Editors and Journalists; Collier
Book/Macmillan Publishing Co.: New York, 1982.
Rosenthal, L. C. “Writing across the curriculum: Chemistry lab reports”, J. Chem. Educ. 1987,
64(12), 996-998.
Schoenfeld, The Chemist’s English, 3rd ed.; VCH Publishers: New York, 1989.
Strunk, W., Jr.; White, E. B. The Elements of Style, 3rd ed., Macmillan Publishing Co.: New
York, 1979.
Weiss, E. H. The Writing System for Engineers and Scientists; Prentice-Hall: Englewood Cliffs,
NJ, 1982.
Wilson, E. B., Jr. An Introduction to Scientific Research; McGraw-Hill: New York, 1952; in
paperback reprint by Dover Publications.
Zinsser, W. K. On Writing Well: An Informal Guide to Writing Nonfiction, Revised and enlarged
3rd ed.; Harper & Row: New York, 1976.
80
6.1 Lab Report 1 Guidelines, Spring 2022:
Synthesis and characterization of [Co(NH 3)4CO3]NO3 and [Co(NH3)5Cl]Cl2
The laboratory report should be in an ACS style and include a title page, an abstract,
introduction, experimental, results and discussion, and references (minimum three
references from the primary literature). If you are unable to access a reference, contact your
instructor for assistance. Follow the guidelines given in the laboratory manual, Canvas, and
consult the ACS style guide. Staple or clip the pages and turn in a printed copy with the
written text at the front and the labeled and organized spectroscopic data at the end. Submit
an electronic copy of the written portion of the laboratory report via Canvas upload. It is
strongly recommended that you visit office hours if you have questions.
 Show all calculations (this is not required to be typed) in an appendix, with each
calculation clearly numbered and labeled.
 Figures and Tables are to be numbered, have descriptive captions, and be cited in text.
 Avoid the use of the term ‘product’, specify the correct formula.
 Check spelling, verb tenses, and grammar.
 Use consistent and correct reference format.
 The results and discussion section is expected to be the largest section of the report.
o Did your synthesis produce the desired product? Support your answer using the
evidence obtained from an analysis of the experimental data (i.e. IR, UV-Vis,
conductivity, magnetic susceptibility, etc.).
Additional considerations are given below for the first report, which you should use as
a general guide for subsequent lab reports. Compare the starting reagent and each of the
synthesized compounds and determine if the syntheses were successful. Support your
claims with an interpretation of the experimental data. Citations to the peer-reviewed
literature or reference source are required to support claims.
 Include the calculation for the product yields (using correct significant figures).
Balance the following chemical reaction:
_Co(NO3)2 + _NH3(aq) + _(NH4)2CO3 + _H2O2 → _[Co(NH3)4CO3]NO3 + _NH4NO3
+_H2O.
 What is the limiting reagent in the reaction?
 Calculate the theoretical yield and percent yield of [Co(NH3)4CO3]NO3 and
[Co(NH3)5Cl]Cl2. Be sure to consider the significant figures involved in the weighing
of the reactants. Comment on possible reasons as to why the percent yield is not exactly
100%.
 What is the purpose of each reagent in the reactions? Why was it used in the synthesis?
 Draw the most likely structures of Co(NO3)2▪6H2O, [Co(NH3)5Cl]Cl2, and
[Co(NH3)4CO3]NO3. Name each of the compounds.
 How can you maximize the purity of each compound?
 Interpret the IR spectra and an assignment of peaks, comparing to known compounds
with similar functional groups and/or the spectra obtained from the literature.
o Reporting peaks to the nearest integer cm-1, not 0.01 cm-1 from peak finding.
o Each IR spectrum should have your name(s) and chemical formula.
o As the synthesis proceeded, compare the similarities and changes in each step
of the synthesis.
81
 Interpret and explain the UV-Vis spectra. Refer to section 20.7, Housecroft and Sharpe,
5e for guidance in the following interpretations and explanation.
o UV-Vis spectra should list the formula, mass and volume used, concentration,
w/ units.
o Note colors of the various compounds and relate to the absorption maxima in
the UV-visible spectra.
o Explain the number of observed peaks. Compare to expected number of
absorptions given geometry, dn -electron count, field strength, and TanabeSugano diagram.
o Explain the magnitude of the molar absorptivity in terms of the molecular
structure and symmetry for each compound. (spin allowed/forbidden; Laporte
allowed/forbidden, centrosymmetric vs noncentrosymmetric). See section 20.7
and Table 20.8 of Housecroft and Sharpe, Inorganic Chemistry (5e)
o Explain changes in wavelength(s) of maximum absorption and the reasoning
behind why it changed.
o Explain changes in molar absorptivity and the reasoning behind why it changed.
o Utilize the concepts of spectrochemical series and the Tanabe-Sugano diagram
in the interpretations.
o Explain how these observations are related to the spectrochemical series and
Δoct and the factors that affect the crystal field stabilization energy.
 Compare the difference in Δoct of [Co(NH3)5Cl]3+ and [Co(NH3)6]3+
(Table 20.2 textbook)
o Explain the magnitude of the molar absorptivity and the relation to the type of
electronic transition and corresponding molecular structures.
o Include a Beer’s Law plot for starting cobalt(II) nitrate hexahydrate reagent,
along with average molar absorptivity and the molar absorptivity from the one
sample you measured.
 Calculate, interpret, and explain the values & differences that you observed in the
conductance of the solutions and molar conductivities of:
o DI water vs tap water. Why differences in conductivity?
o Conductance data must include mass of solute, volume of solution, measured
conductivity value, and units on measured value (milli S ≠ micro S).
o KCl, MgCl2, [Co(NH3)4CO3]NO3 and [Co(NH3)5Cl]Cl2.
 Explain how many ions are formed in solution.
 Explain the observed versus expected molar conductivity values.
 Include and explain the magnetic susceptibility data [i.e. compare eff and (spin only)].
o Magnetic susceptibility data should be a separate table and for each compound
include chemical formula, mass, height of sample tube, numerical value with
+/- sign from the measurement, and temperature with units.
o Determine and explain if the measured magnetic susceptibilities and magnetic
moments 1) agree with the predicted magnetic moment considering the spin
only contribution and 2) are within the typical range observed as found in Table
20.11 in Housecroft and Sharpe, Inorganic Chemistry, 5e.
o Another approach would also include orbital contribution, and consideration of
typical magnetic moments for specific dn complexes. See section 20.10,
Housecroft and Sharpe, 5e for guidance in the above interpretations.
82
Supporting information tables. Include these completed tables as supporting information.
Create your own numbered tables for calculated values in the results and discussion
section.
Table S1: Summary raw data, synthesis.
Mass of limiting
reactant used in
synthesis (g)
Formula
[Co(H2O)6](NO3)2
[Co(NH3)4CO3]NO3
Mass of product
obtained from
synthesis (g)
Formula
[Co(NH3)4CO3]NO3
[Co(NH3)5Cl]Cl2
Table S2: Summary raw data, UV-Vis.
Mass used
to prepare
solution
(g)
Formula
Volume
of
Solution
(mL)
Absorbance
Maximum(s)
Wavelength(s) of
maximum
absorbance (nm)
[Co(H2O)6](NO3)2
[Co(NH3)4CO3]NO3
[Co(NH3)5Cl]Cl2
Table S3: Summary raw data, magnetic susceptibility.
Formula
Length
(cm)
Mass (g)
Temperature
(°C)
R0
[Co(H2O)6](NO3)2
[Co(NH3)4CO3]NO3
[Co(NH3)5Cl]Cl2
Table S4: Summary raw data, conductance.
Formula
Mass (g)
[Co(H2O)6](NO3)2
[Co(NH3)4CO3]NO3
[Co(NH3)5Cl]Cl2
KCl
MgCl2
83
Volume of
Solution
(mL)
Conductance
(specify
units)
R
Calculations: It is suggested to perform calculations in Excel. Show steps in the calculation,
which can be written by hand or typed. Include units on numbers as appropriate. Use
appropriate significant figures. The calculations should be numbered as given below and
placed in Appendix A. Number any additional calculation sequentially after this list.
Calculation 1: Percent yield for [Co(NH3)4CO3](NO3)
Calculation 2: Theoretical yield for [Co(NH3)5Cl]Cl2
Calculation 3: Percent yield for [Co(NH3)5Cl]Cl2
Calculation 4: Molar absorptivity, [Co(OH2)6](NO3)2], individual measurement
Calculation 5: Molar absorptivity, [Co(OH2)6](NO3)2, multiple measurements, slope of Beer's Law
graph
Calculation 6: Percent difference of individual molar absorptivity and slope from trendline
Calculation 7: Prepared solution molarity of [Co(NH3)4CO3]NO3*0.5H2O
Calculation 8: Molar absorptivity, [Co(NH3)4CO3]NO3*0.5H2O
Calculation 9: Prepared solution molarity of [Co(NH3)5Cl]Cl2
Calculation 10: Molar absorptivity, [Co(NH3)5Cl]Cl2
Calculation 11: Prepared solution molarity calculation KCl (assigned concentration or 0.0100 M)
Calculation 12: Molar conductivity, KCl (assigned concentration or 0.0100)
Calculation 13: Prepared solution molarity calculation KCl (approx 0.00500 M)
Calculation 14: Molar conductivity, KCl (0.00500 M)
Calculation 15: Prepared solution molarity calculation MgCl2 (approx 0.00500 M)
Calculation 16: Molar conductivity, MgCl2
Calculation 17: Prepared Molarity calculation [Co(OH2)6](NO3)2 (approx 0.00500 M)
Calculation 18: Molar conductivity, [Co(OH2)6](NO3)2
Calculation 19: Prepared solution molarity calculation [Co(NH3)4CO3]NO3*0.5H2O (approx 0.00500
M)
Calculation 20: Molar conductivity, [Co(NH3)4CO3]NO3*0.5H2O
Calculation 21: Prepared Molarity calculation [Co(NH3)5Cl]Cl2 (approx 0.00500 M)
Calculation 22: Molar conductivity, [Co(NH3)5Cl]Cl2
Calculation 23: Magnetic susceptibility balance calibration constant, Cbal
Calculation 24: Mass magnetic susceptibility, χ(g), [Co(OH 2)6](NO3)2
Calculation 25: Molar magnetic susceptibility, χ(m), [Co(OH 2)6](NO3)2
Calculation 26: Molar magnetic susceptibility corrected for diamagnetic contributions, X(A),
[Co(OH2)6](NO3)2
Calculation 27: Effective magnetic moment, mu-eff [Co(OH 2)6](NO3)2
Calculation 28: Mass magnetic susceptibility, χ(g), [Co(NH3)4CO3]NO3*0.5H2O
Calculation 29: Molar magnetic susceptibility, χ(m), [Co(NH3)4CO3]NO3*0.5H2O
Calculation 30: Molar magnetic susceptibility with diamagnetic corrections, X(A),
[Co(NH3)4CO3]NO3*0.5H2O
Calculation 31: Effective magnetic moment, mu-eff [Co(NH3)4CO3]NO3*0.5H2O
Calculation 32: Mass magnetic susceptibility, χ(g), [Co(NH3)5Cl]Cl2
Calculation 33: Molar magnetic susceptibility, χ(m), [Co(NH3)5Cl]Cl2
Calculation 34: Molar magnetic susceptibility with diamagnetic corrections X(A), [Co(NH 3)5Cl]Cl2
Calculation 35: Effective magnetic moment, mu-eff [Co(NH3)5Cl]Cl2
Calculation 36: Determination of delta-oct using Tanabe-Sugano diagram, [Co(NH 3)4CO3]NO3
Calculation 37: Determination of delta-oct using Tanabe-Sugano diagram, [Co(NH 3)5Cl]Cl2
Calculation 38: Determination of difference (in cm-1) between delta-oct [Co(NH3)5Cl]3+ and
[Co(NH3)6]3+ [include sign (+/-) of difference] Table 20.2 Housecroft and Sharpe 5e)
84
6.2 Lab Report 2 Guidelines, Spring 2022:
Synthesis and Characterization of Cobalt-containing Linkage Isomers
[Co(NH3)5ONO]Cl2 and [Co(NH3)5NO2]Cl2 and the Enantiomers
Co(en)3X3
The Spring 2022 laboratory report 2 should be in ACS style and include a title page, an
abstract, introduction, experimental, results and discussion, references and data. Follow the
guidelines given in the course handout. Include in the results and discussion the calculation
for the product yield (using significant figures), interpretation/explanation of the IR spectra
and assignment of absorption peaks for the starting material and product(s), and
interpretation/explanation of the UV-Vis spectra (wavelength of maximum absorption,
molar absorptivity) and the relation to the structures.
Ensure the laboratory report includes:
□ Title: Pertinent and descriptive
□ Introduction:
o Background with primary references from peer reviewed literature
□ Experimental:
o Synthesis, including chemicals used, etc.
o Descriptions of instrumentation and scan conditions so that someone could
reproduce your results.
o All experimental IR and UV-Vis spectra have appropriate labels and titles.
o Include the full sheet printed spectra at the end of your report.
o Mass of solute and volume should be included on each UV-Vis spectrum
□ Results and Discussion:
□ Include the Lewis structures of the nitro and nitrito ligands and how this influences the
initial reaction product. Prepare a hypothesis as to why [Co(NH3)5ONO]Cl2 rather than
[Co(NH3)5NO2]Cl2 is formed in the conditions of this synthesis.
□ Explain how the enantiomers were separated.
□ Calculation of product yields.
o Be sure to consider the significant figures involved in the weighing of the reactants.
o Comment on possible reasons as to why the percent yield is more or less than 100%.
□ Compare and contrast the changes in the IR spectra for reactant and product(s)
□ Interpretation of the IR spectra
o Attempt assignment of peaks for reactants and product(s).
o Compare changes to starting material with compounds in each step of the synthesis.
o Include pertinent literature citation(s) to any of the peak assignments. Support
claims.
□ Interpretation of the UV-Vis spectra
o Colors of compound(s) and the position(s) of the wavelength of maximum
absorption.
 Explain any changes in the observed colors compared to Co(H2O)6Cl2 and
relation to the UV-Vis spectra. If color changes, why?
85

Consider and discuss the differences between the two linkage isomers, in
both the UV-Vis spectra, including the difference in absorption maxima and
the observed color.
 Explain the effect on UV-Vis spectra, if any, of having different counter
ions on the enantiomers. Is this expected, or unexpected?
 Explain the difference in UV-Vis spectra, if any, between the (+) and (-)
enantiomers. Is this expected, or unexpected?
o Wavelength(s) of maximum absorption
 Note and explain shifts in how this corresponds to changes in changes in
oxidation state of metal of reactant compared to products, ligand(s) and their
position in the spectrochemical series, crystal field splitting energy, Δ o, etc.
o Calculation of molar absorptivity for each compound with correct units (L mol -1
cm-1)
 Do this for Co(H2O)6Cl2 and all subsequent cobalt-containing samples.
 To what type of absorption(s) do these correspond?
 Laporte allowed? Laporte forbidden? spin allowed? spin forbidden?
d to d? Charge transfer?
 Explain the roles of the changes in ligands and symmetry on the value of
molar absorptivity.
o Determine the value(s) of Δ0 using the appropriate Tanabe-Sugano diagram.
 Compare your determined values of Δ0 to the value listed for Co(en)33+ in
the Housecroft and Sharpe (5e) textbook table 20.2.
Magnetic susceptibility
o Determine if each metal containing compound is paramagnetic or diamagnetic
 Explain why in terms of factors that influence Δ o
o Calculate the effective magnetic moments and compare to spin only value and
typical range when orbital and other contributions are considered
Polarimetry
o Note if optical rotation was observed on tartaric acid.
 Perform quantitative calculation for specific rotation angle of tartaric acid.
 Compare to literature value, i.e. specification and properties at:
https://www.tcichemicals.com/US/en/p/T0025
 Comment on the +/- direction of rotation and perform quantitative
calculation for specific rotation angles of [(+)Co(en)3]I3•H2O and
[(+)Co(en)3]I3•H2O
86
These supplemental tables should be completed and present in an appendix.
Create your own tables for calculated information (e.g. molar extinction coefficient,
effective magnetic moment etc.)
Table S1: Summary raw data, synthesis.
Formula
CoCl2·6H2O
[(+)Co(en)3]Cl3•1/2NaCl•3H2O
[(+)Co(en)3][(+)tart]Cl·5H2O
[(-)Co(en)3]Cl3•1/2NaCl•3H2O
Mass of
limiting
reactant
used in
synthesis (g)
Mass of
product
obtained from
synthesis (g)
Formula
[Co(en)3]Cl3•1/2NaCl•3H2O
[(+)Co(en)3][(+)tart]Cl·5H2O
[(+)Co(en)3]I3•H2O
[(-)Co(en)3]I3•H2O
Table S2: Summary raw data, UV-Vis.
Mass used
to prepare
solution
(g)
Compound
Volume
of
Solution
(mL)
Wavelength(s)
of maximum
absorbance
(nm)
Absorbance
Maximum(s)
CoCl2•6H2O
[Co(NH3)5Cl]Cl2
[Co(NH3)5ONO]Cl2 (week 1)
[Co(NH3)5ONO]Cl2 (week 2)
[Co(NH3)5ONO]Cl2 (week 3)
[(+)Co(en)3]Cl3•1/2NaCl•3H2O
[(+)Co(en)3][(+)tart]Cl·5H2O
[(+)Co(en)3]I3•H2O
[(-)Co(en)3]I3•H2O
Table S3: Summary raw data, magnetic susceptibility.
Compound
Length
(cm)
Mass (g)
Temperature
(°C)
R0
R
CoCl2•6H2O
[Co(NH3)5Cl]Cl2
[Co(NH3)5ONO]Cl2 (any week)
[(+)Co(en)3]Cl3•1/2NaCl•3H2O
[(+)Co(en)3][(+)tart]Cl·5H2O
[(+)Co(en)3]I3•H2O
[(-)Co(en)3]I3•H2O
Table S4: Summary raw data, polarimetry.
Compound
length of
polarimeter
tube (dm)
mass
sample (g)
diammonium tartrate
[(+)Co(en)3]I3•H2O
[(-)Co(en)3]I3•H2O
87
volume (mL)
observed
rotation
angle
(alpha)
Temperature
(°C)
Calculations: It is suggested to perform calculations in Excel. Show steps in
the calculation, which can be written by hand or typed. Include units on
numbers as appropriate. Use appropriate significant figures. The calculations
should be numbered as given below and placed in Appendix A. Number any
additional calculation sequentially after this list.
Linkage Isomers
Calculation 1. Theoretical yield [Co(NH3)5ONO]Cl2
Calculation 2. Percent yield [Co(NH3)5ONO]Cl2
Calculation 3. Prepared solution molarity of CoCl2·6H2O
Calculation 4. Molar absorptivity, CoCl2·6H2O
Calculation 5. Prepared solution molarity of [Co(NH3)5Cl]Cl2
Calculation 6. Molar absorptivity, [Co(NH3)5Cl]Cl2
Calculation 7. Prepared solution molarity of [Co(NH3)5ONO]Cl2 (week 1) at lambda max
near 450-460 nm
Calculation 8. Molar absorptivity, [Co(NH3)5ONO]Cl2 (week 1), peak near 450 nm
Calculation 9. Prepared solution molarity of [Co(NH3)5ONO]Cl2 / [Co(NH3)5NO2]Cl2
(week 2)
Calculation 10. Molar absorptivity, [Co(NH3)5NO2]Cl2 (week 2)
Calculation 11. Prepared solution molarity of [Co(NH3)5NO2]Cl2 (week 3)
Calculation 12. Molar absorptivity, [Co(NH3)5NO2]Cl2 (week 3)
Calculation 13. Molarity after (1:50) dilution of ~0.00500 M [Co(NH3)5NO2]Cl2, 1.00 mL
to 100.00 mL
Calculation 14. Molar absorptivity, [Co(NH3)5NO2]Cl2 (any week) peak near 325 nm
Calculation 15: Magnetic susceptibility balance calibration constant, C bal
Calculation 16: Mass magnetic susceptibility, χ(g), [Co(OH2)6]Cl2
Calculation 17: Molar magnetic susceptibility, χ(m), [Co(OH2)6]Cl2
Calculation 18: Molar magnetic susceptibility corrected for diamagnetic contributions,
X(A), [Co(OH2)6]Cl2
Calculation 19: Effective magnetic moment, mu-eff [Co(OH2)6]Cl2
Calculation 20: Mass magnetic susceptibility, χ(g), [Co(NH3)5Cl]Cl2
Calculation 21: Mass magnetic susceptibility, χ(g), [Co(NH3)5ONO]Cl2 (any week)
Calculation 22: Determination of delta-oct using Tanabe-Sugano diagram, [Co(NH3)5Cl]Cl2
88
Enantiomers
Calculation 1. Theoretical yield (g) of [Co(en)3]Cl3•1/2NaCl•3H2O(s)
Calculation 2. Percent yield of [Co(en)3]Cl3•1/2NaCl•3H2O(s)
Calculation 3. Split grams of [(+)Co(en)3]Cl3•1/2NaCl•3H2O(s) and [()Co(en)3]Cl3•1/2NaCl•3H2O(s)
Calculation 4. Theoretical yield (g) of [(+)Co(en)3][(+)tart]Cl·5H2O
Calculation 5. Percent yield of [(+)Co(en)3][(+)tart]Cl·5H2O
Calculation 6. Theoretical yield (g) of [(+)Co(en)3]I3•H2O
Calculation 7. Percent yield of [(+)Co(en)3]I3•H2O
Calculation 8. Theoretical yield (g) of [(-)Co(en)3]I3•H2O, assume 100% yield present in
decantated solution
Calculation 9. Percent yield of [(-)Co(en)3]I3•H2O
Calculation 10. Prepared solution molarity of [Co(en)3]Cl3•1/2NaCl•3H2O(s)
Calculation 11. Molar absorptivity, [Co(en)3]Cl3•1/2NaCl•3H2O(s)
Calculation 12. Prepared solution molarity of [(+)Co(en)3][(+)tart]Cl·5H2O
Calculation 13. Molar absorptivity, [(+)Co(en)3][(+)tart]Cl·5H2O
Calculation 14. Prepared solution molarity of [(+)Co(en)3]I3•H2O
Calculation 15. Molar absorptivity, [(+)Co(en)3]I3•H2O
Calculation 16. Prepared solution molarity of [(-)Co(en)3]I3•H2O
Calculation 17. Molar absorptivity, [(-)Co(en)3]I3•H2O
Calculation 18: Magnetic susceptibility balance calibration constant, C bal
Calculation 19: Mass magnetic susceptibility, χ(g), [Co(OH2)6]Cl2
Calculation 20: Molar magnetic susceptibility, χ(m), [Co(OH2)6]Cl2
Calculation 21: Molar magnetic susceptibility corrected for diamagnetic contributions,
X(A), [Co(OH2)6]Cl2
Calculation 22: Effective magnetic moment, mu-eff [Co(OH2)6]Cl2
Calculation 23: Mass magnetic susceptibility, χ(g), [(+)Co(en)3]Cl3•1/2NaCl•3H2O(s)
Calculation 24: Mass magnetic susceptibility, χ(g), [(+)Co(en)3][(+)tart]Cl·5H2O
Calculation 25: Mass magnetic susceptibility, χ(g), [(+)Co(en)3]I3•H2O
Calculation 26: Mass magnetic susceptibility, χ(g), [(-)Co(en)3]I3•H2O
Calculation 27. Polarimetry, specific rotation tartaric acid
Calculation 28. Polarimetry, specific rotation [(+)Co(en)3]I3•H2O
Calculation 29. Polarimetry, specific rotation [(-)Co(en)3]I3•H2O
Calculation 30: Determination of delta-oct using Tanabe-Sugano diagram,
[(+)Co(en)3]Cl3•1/2NaCl•3H2O
Calculation 31: Determination of delta-oct using Tanabe-Sugano diagram,
[(+)Co(en)3][(+)tart]Cl·5H2O
Calculation 32: Determination of delta-oct using Tanabe-Sugano diagram,
[(+)Co(en)3]I3•H2O
Calculation 33: Determination of delta-oct using Tanabe-Sugano diagram,
[(-)Co(en)3]I3•H2O
89
Table S5: Summary of results for [Co(NH3)5ONO]Cl2 / [Co(NH3)5NO2]Cl2 linkage isomers
Value
Units
Percent yield [Co(NH3)5ONO]Cl2
%
Molar absorptivity, [Co(H2O)6]Cl2
M-1 cm-1
Molar absorptivity, [Co(NH3)5Cl]Cl2
M-1 cm-1
Molar absorptivity, [Co(NH3)5ONO]Cl2 (week 1), peak near 450 nm
Molar absorptivity, [Co(NH3)5ONO]Cl2 / [Co(NH3)5NO2]Cl2 (week 2),
peak near 450 nm
M-1 cm-1
Molar absorptivity, [Co(NH3)5NO2]Cl2 (week 3), peak near 450 nm
M-1 cm-1
Molar absorptivity, [Co(NH3)5NO2]Cl2 (any week) peak near 325 nm
M-1 cm-1
M-1 cm-1
Wavelength of maximum absorbance, [Co(H2O)6]Cl2
nm
Wavelength of maximum absorbance, [Co(NH3)5ONO]Cl2 (week 1)
Wavelength of maximum absorbance, [Co(NH3)5ONO]Cl2 /
[Co(NH3)5NO2]Cl2 (week 2)
nm
Wavelength of maximum absorbance, [Co(NH3)5NO2]Cl2 (week 3)
nm
Effective magnetic moment, μeff [Co(H2O)6]Cl2
BM
Effective magnetic moment, μeff [Co(NH3)5ONO]Cl2 (any week)
BM
Δoct using Tanabe-Sugano diagram, [Co(NH3)5Cl]Cl2
cm-1
90
nm
Table S6: Summary of results for [Co(en)3]X3 enantiomers
Value
Units
Percent yield [Co(en)3]Cl3•1/2NaCl•3H2O(s)
%
Percent yield of [(+)Co(en)3][(+)tart]Cl·5H2O
%
Percent yield of [(+)Co(en)3]I3•H2O
%
Percent yield of [(-)Co(en)3]I3•H2O
%
Molar absorptivity, [Co(H2O)6]Cl2
M-1 cm-1
Molar absorptivity, [Co(en)3]Cl3•1/2NaCl•3H2O(s)
M-1 cm-1
Molar absorptivity, [(+)Co(en)3][(+)tart]Cl·5H2O
M-1 cm-1
Molar absorptivity, [(+)Co(en)3]I3•H2O
M-1 cm-1
Molar absorptivity, [(-)Co(en)3]I3•H2O
M-1 cm-1
Wavelength of maximum absorbance, [Co(H2O)6]Cl2
Wavelengths of maximum absorbance,
[Co(en)3]Cl3•1/2NaCl•3H2O(s)
nm
Wavelengths of maximum absorbance, [(+)Co(en)3][(+)tart]Cl·5H2O
nm
Wavelengths of maximum absorbance, [(+)Co(en)3]I3•H2O
nm
Wavelengths of maximum absorbance, [(-)Co(en)3]I3•H2O
nm
Effective magnetic moment, μeff [Co(H2O)6]Cl2
BM
Effective magnetic moment, μeff [Co(en)3]Cl3•1/2NaCl•3H2O(s)
BM
Effective magnetic moment, μeff [(+)Co(en)3][(+)tart]Cl·5H2O
BM
Effective magnetic moment, μeff [(+)Co(en)3]I3•H2O
BM
Effective magnetic moment, μeff [(-)Co(en)3]I3•H2O
BM
Δoct using Tanabe-Sugano diagram, [Co(en)3]Cl3•1/2NaCl•3H2O(s)
cm-1
Δoct using Tanabe-Sugano diagram, [(+)Co(en)3][(+)tart]Cl·5H2O
cm-1
Δoct using Tanabe-Sugano diagram, [(+)Co(en)3]I3•H2O
cm-1
Δoct using Tanabe-Sugano diagram, [(-)Co(en)3]I3•H2O
optical activity, L-(+)-tartaric acid diammonium salt
% error, optical activity, L-(+)-tartaric acid diammonium salt
cm-1
°
%
nm
optical activity, [(+)Co(en)3]I3•H2O
°
optical activity, [(-)Co(en)3]I3•H2O
°
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6.3 Lab Report 3 Guidelines:
Synthesis and Characterization of a Light-Emitting Diode,
[Ru(bpy)3](BF4)2
The Spring 2022 laboratory report 3 should be in ACS style and include a title page, an
abstract, introduction, experimental, results and discussion, references, and data (including
spectra). Include a completed supporting information page (provided as a Word document
on Canvas) in your lab report. Follow the provided guidelines. Ensure the laboratory report
includes the following:
Title:
□ Pertinent and descriptive
Introduction:
□ Background with primary references from peer-reviewed and published literature in a
reputable journal.
□ Theory of LED (molecular) and the mechanism of light emission in this complex
Experimental:
□ Synthesis, including chemicals used, etc.
□ Descriptions of instrumentation and scan conditions. Ensure it is reproducible to a reader.
□ All experimental IR and UV-Vis spectra have appropriate labels and titles.
□ Include the full sheet spectra at the end of your report as a numbered figure with a figure
caption.
o For UV-Vis spectra, include the molarity of solution in the figure caption.
□ Identity of solute, mass of solute, and volume of solution should be included on the UVVis spectrum.
o Any dilutions should be described.
□ Details on the fabrication of light emitting diode (LED)
□ Details on the measurement of the emission spectrum. An Ocean Optics Red Tide USB650
with UV/VIS Fiber Optic was used to measure the emission spectrum in the range 3501000 nm.
□ Details on the thermogravimetric analysis of RuCl3·3H2O. Instrument: TA SDT 650
Discovery Series TGA-DSC. Data collection Ramp 3 °C/min to 275.00 °C.
Results and Discussion:
□ Include the calculation for the percent yield
o Be sure to consider the significant figures involved in the weighing of the reactants.
o Comment on possible reasons as to why the percent yield not 100%.
o Include the structure of the coordination complex.
 Sketch by hand is okay, but if you did not draw it (cite source) or if you create
it in software.
□ Interpretation of the IR spectra
o Compare and contrast the changes in the in the IR for reactants (i.e. RuCl3, NaBF4,
2,2′-bipyridine) and product ([Ru(bpy)3](BF4)2)
o Attempt assignment of peaks for reactants and product(s).
o Include pertinent literature citation(s) to any of the peak assignments.
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 Support claims.
□ Interpretation of the UV-Vis spectra
o Discuss dilutions and reason for doing so.
o Colors of compound(s) and the position(s) of the wavelength of maximum absorption.
 Explain the color changes and observed color and relation to the UV-Vis
spectra.
o Calculation of molar absorptivity with correct units (L mol-1 cm-1)
 To what type of absorption does this correspond? Spin allowed or forbidden?
Laporte allowed or forbidden? Charge transfer? If charge transfer, what type
– MLCT or LMCT?
□ Magnetic susceptibility
o Determine if [Ru(bpy)3](BF4)2 is paramagnetic or diamagnetic
 Explain why in terms of the d electron count and four factors that influence Δo
o If paramagnetic, calculate the effective magnetic moment and compare to spin only
value and typical range when orbital and other contributions are considered
□ LED - Observations and discussion on your constructed LED
o Include photo, if possible, of the functional LED.
□ Emission Spectrum – Create a quality graph of intensity (counts) vs. wavelength (nm).
Ensure the x-axis and y-axis are labeled. Comment on wavelength of maximum emission
intensity and the observed color.
□ TGA data: interpret the data and explain mass loss. Hint: compare molar mass ratio of
RuCl3 to RuCl3·3H2O to find expected mass loss. Compare to the observed mass loss (prior
to decomposition, which occurs above 300 °C). Create a graph of weight % vs.
Temperature (°C). Use a y-axis data range of 75 to 101% and an x-axis range of 25 to 275
°C.
Conclusions and References:
□ Include citations from the primary literature.
Calculations
Calculation 1. Theoretical yield (g) [Ru(bpy)3](BF4)2
Calculation 2. Percent yield [Ru(bpy)3](BF4)2
Calculation 3. Prepared solution molarity (M) of [Ru(bpy) 3](BF4)2. Show calculations for
dilutions.
Calculation 4. Molar absorptivity, [Ru(bpy)3](BF4)2
Calculation 5: Magnetic susceptibility balance calibration constant, C bal
Calculation 6: Effective magnetic moment, μ eff, [Ru(bpy)3](BF4)2
Calculation 7: Expected mass % loss for RuCl 3·3H2O(s) → RuCl3(s) + 3H2O(g)
Include other calculations as needed.
93
6.4 Lab Report 4 Guidelines:
Synthesis and characterization of air sensitive CuCl and YBa2Cu3O7-x
superconductor
The Spring 2022 laboratory report 4 is in a simplified format compared to lab reports 1-3.
1) A Microsoft Word (or equivalent) document containing tables with pertinent
numerical data and calculations.
a) The product yield of CuCl (using significant figures). Show all calculations on a
separate written sheet using correct significant figures and units.
b) Magnetic susceptibility for CuCl2 and CuCl. Include calculations and a paragraph or
two of interpretation of the data.
b) Applied load for pellet pressing. Determine the percent (%) density for the pellet. The
% density is the measured density/theoretical density from the crystal structure.
i.
Determine the measured density by calculating mass (g)/volume (cm 3).
Determine the volume of the pellet by measuring the thickness and
diameter and calculating the volume assuming it is a cylinder.
ii.
The theoretical density (in g/cm3) can be determined from the mass of all
the atoms in the unit cell divided by the volume of the unit cell from the
CIF file chosen below. Note, 1 Angstrom = 1×10 -10 m.
2) A PowerPoint (or equivalent) document containing
a) Create crystal structure figures for CuCl and YBa 2Cu3O7-x. Crystal structure
information in the CIF file format (text) can be obtained from the Crystallography Open
Database http://www.crystallography.net/cod/. For YBa2Cu3O7-x, include the elements Y,
Ba, Cu, and O and a minimum and maximum number of elements of 4 and 4,
respectively. Choose a structure with space group Pmmm, e.g. 1539699 cif file for
YBa2Cu3O6.73. The free software program VESTA may be downloaded at
http://www.jp-minerals.org/vesta/en/download.html and used to generate the crystal
structure. Be sure to properly cite which structure you used.
b) full size image(s) of the sealed CuCl ampoule.
c) full size images, at least two, of the demonstration of YBa2Cu3O7-x pellet exhibiting the
Meissner effect. Include a different number of miniature magnets in each photo.
3) Video (about 5-15 s) of a magnet or magnets levitated above the superconductor pellet
and demonstrating the Meissner effect.
94