Download Nomenclature Notes

Things you should already know how
to do so we won’t go over them again:
Nomenclature
Chemistry 11 Honours
• Count protons, electrons and neutrons
from atomic symbols
• Count the number of atoms in a formula
• Identify compounds as ionic or molecular
(covalent)
• Name ionic compounds
• with polyatomic ions and multivalent ions
• Name covalent compounds
• using prefixes
Writing Dissociation Equations:
(comes up again in Chem 12)
• When ionic compounds are put in water,
they dissociate (a.k.a. dissolve - split into
their ions)
• Knowing the ions that make up a compound
can help you name it!
• An aqueous solution is formed containing
the ions that made up the ionic salt
• Example:
NaCl(s) → Na+(aq) + Cl-(aq)
Common Names for Ionic Compounds:
(these don’t follow the rules)
• Old way of naming compounds with multivalent
ions
• multivalent ions are named according to their Latin
names, rather than using Roman numerals
• Name the Latin root for the ion, then change the
ending
• The lower charge ion ends in “ous”
• The higher charge ion ends in “ic”
• Ex. FeCl2 = ferrous chloride = iron(II) chloride
FeCl3 = ferric chloride = iron(III) chloride
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Naming Acids:
Naming Binary Acids:
• How do you know if the compound is an acid?
•
• the formula has an “H” at the front
• One exception we worry about…
CH3COOH or C2H4O2 = acetic acid
• the name ends in “acid”
•
•
•
Hydro_________ic acid
ex. HCl
Second ion = Cl- = Chloride
Acid name = hydrochloric acid
• 3 types of acids to name:
• binary acids – contain ions ending in “ide”
• acids containing polyatomic ions ending in “ate”
• acids containing polyatomic ions ending in “ite”
Naming Acids with Polyatomic
Ions Ending in “ate”:
• ____________ic acid
• ex. HNO3
• polyatomic ion = NO3- = Nitrate
• Acid name = Nitric acid
Naming Acids with Polyatomic
Ions Ending in “ite”:
• ____________ous acid
• ex. HNO2
• polyatomic ion = NO2- = Nitrite
• Acid name = Nitrous acid
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Writing Formulas for Acids:
•
The hydrogen always is written first
(except in acetic acid – CH3COOH)
ex. Hydrochloric acid
•
•
•
•
Hydrochloric = chloride = ClNeed 1 H+ to match up the charges
Formula = HCl
• Example #1:
Naming Hydrates:
• Hydrate: an ionic salt that has water
associated with it (incorporated into the
crystal lattice structure)
• Named just like ionic compounds,
except…
• the Greek prefixes are added at the end
with the word “hydrate” to show how many
water molecules are present
• A dot is added between the formula of the
salt and the formula of the water
The “Weirdo’s”
• iron(III) phosphate octahydrate
• iron(III) = Fe3+ phosphate = PO43• octahydrate = 8H2O
• ∴ FePO4 · 8H2O
• Example #2:
• Na2SO4 · 10H2O
• Na+ = sodium SO42- = sulphate
• 10 H2O = decahydrate
• ∴ sodium sulphate decahydrate
• Unlike other metals, transition metals
show great similarities within a given
period and group.
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• Exhibit the following characteristics:
• Form more than one oxidation state/charge.
• The cations are often complex ions.
• The transition metal is surrounded by a certain
number of ligands (molecules or ions that bond
to a metal ion).
[Co(NH3)6]Cl3
K3[Fe(CN)6]
• Most compounds are coloured.
Coordination Compounds
• Formed by transition metal ions.
• Consists of a complex ion (a transition
metal with its attached ligands, NH3 and
Cl-) and counterions (ions to balance
out charge).
• For Example:
[Co(NH3)5Cl]Cl2
Co3+
• When these compounds dissolve in
water, they usually produce coloured
solutions that act as ionic compounds:
[Co(NH3)5Cl]Cl2(s)→Co(NH3)5Cl2+(aq) + 2Cl-(aq)
Coordination Number:
• The number of bonds formed by metal
ions to ligands varies from two to eight.
• Depends upon the size, charge, and
electron configuration of the transition
metal ion
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Ligands:
• Each coordination
number will produce a
different geometry
(we’ll talk more about this
later in course).
• A neutral molecule or ion having a
lone electron pair that can be used
to form a bond to a metal ion.
• Monodentate Ligand:
• Also called unidentate ligand.
• Can form one bond to a metal ion.
• Bidentate Ligand:
• Can form two bonds to a metal
ion.
• Chelating Ligand or Chelates:
• More than one atom with a lone
pair that can bond to a metal ion.
Nomenclature
for coordination Compounds
1. To name a coordination compound, no
matter whether the complex ion is the cation
or the anion, always name the cation before
the anion.
2. In naming the complex ion:
a) Name the ligands first, in alphabetical order,
then the metal atom or ion. The metal atom or
ion is written before the ligands in the chemical
formula.
b) See the table on next slide for names of some
common ligands.
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• Anionic ligands end in "-o”.
• Anions that end in "-ide"(e.g. chloride), "-ate"
(e.g. sulfate, nitrate), and "-ite" (e.g. nirite),
change the endings as follows:
• For neutral ligands, the common name
of the molecule is used.
• For example: H2NCH2CH2NH2
(ethylenediamine).
• Important exceptions:
-ide
-ate
-ite
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•
•
•
-o
-ato
-ito
• Greek prefixes are used to designate
the number of each type of ligand in the
complex ion.
• If the ligand already contains a Greek
prefix (e.g. ethylenediamine) or if it is a
polydentate ligand, the prefixes bis-, tris-,
tetrakis-, pentakis-, are used instead.
Water is called ‘aqua’.
Ammonia is called ‘ammine’.
Carbon monoxide is called ‘carbonyl’.
N2 and O2 are called ‘dinitrogen’ and
‘dioxygen’.
Number
Prefix
Number
1
mono
5
2
di (bis)
6
3
tri (tris)
7
4
tetra
(tetrakis)
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Prefix
Number
Prefix
9
nona
(ennea)
10
deca
hepta
11
undeca
octa
12
dodeca
penta
(pentakis)
hexa
(hexakis)
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• After naming the ligands, name the central
metal.
• If the complex ion is a cation, the metal is
named the same as the element.
• If the complex ion is an anion, the name of the
metal ends with the suffix –ate.
Name of Metal
Name in an Anionic
Complex
Iron
Ferrate
Copper
Cuprate
Lead
Plumbate
Silver
Argenate
Gold
Aurate
Tin
Stannate
• Co in a complex anion is called Cobaltate and Pt is
called Platinate.
• For some metals, the Latin names are used in the
complex anions.
• Fe is called Ferrate (not ironate).
• Following the name of the metal, the oxidation
state of the metal in the complex is given as a
Roman numeral in parentheses
Example time…(hope these help)
• Name the following coordination
compounds:
• [Cr(NH3)3(H2O)3]Cl3
triamminetriaquachromium(III) chloride
•
•
•
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The complex ion is inside the parentheses, which is a cation.
The ammine ligands are named before the aqua ligands according to alphabetical order.
Since there are three chlorides binding with the complex ion, the charge on the complex ion must
be +3 ( since the compound is electrically neutral).
From the charge on the complex ion and the charge on the ligands, we can calculate the oxidation
number (charge) of the metal. In this example, all the ligands are neutral molecules. Therefore, the
oxidation number of chromium must be same as the charge of the complex ion, +3.
• [Pt(NH3)5Cl]Br3
pentaamminechloroplatinum(IV) bromide
•
•
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The complex ion is a cation, the counter anion is the 3 bromides.
The charge of the complex ion must be +3 since it bonds with 3 bromides.
The NH3 are neutral molecules while the chloride carries - 1 charge. Therefore, the oxidation
number of platinum must be +4.
• [Pt(H2NCH2CH2NH2)2Cl2]Cl2
dichlorobis(ethylenediamine)platinum(IV) chloride
•
ethylenediamine is a bidentate ligand, the bis- prefix is used instead of di-.
• [Co(H2NCH2CH2NH2)3]2(SO4)3
tris(ethylenediamine)cobalt(III) sulfate
•
•
The sulfate is the counter anion in this molecule. Since it takes 3 sulfates to bond with two
complex cations, the charge on each complex cation must be +3.
Since ethylenediamine is a neutral molecule, the oxidation number of cobalt in the complex ion
must be +3.
• K4[Fe(CN)6]
potassium hexacyanoferrate(II)
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•
•
Potassium is the cation and the complex ion is the anion.
Since there are 4 K+ binding with a complex ion, the charge on the complex ion must be - 4.
Since each ligand carries –1 charge, the oxidation number of Fe must be +2.
• Na2[NiCl4]
sodium tetrachloronickelate(II)
•
The complex ion is the anion so we have to add the suffix –ate in the name of the metal.
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• Write the formulas for the following:
• Hexaammineiron(III) nitrate
[Fe(NH3)6](NO3)3
• Ammonium tetrachlorocuprate(II)
(NH4)2[CuCl4]
• Sodium chloropentacyanoferrate(III)
Na3[Fe(CN)5Cl]
• Potassium hexafluorocobaltate(III)
K3[CoF6]
Homework:
• Nomenclature Worksheet
• Study for quiz
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