Download doc CHEM_110_LECTURE_2_nov_6th

CHEM 110 LECTURE 2 nov 6th 2009
 Amethyst  SiO2, purple variety of quartz, but colour is provided by Mn
 Emerald  colour provided by Cr
 Metal containing compounds play an important role in pigments in
gemstones, paint, photography and act as catalysts (Pt, Pd, Mn)
 LIFE: Fe, Co, Cu  iron essential in transport and storage of oxygen
 Copper and iron have a crucial role in respiration
 Zinc found in more than 150 biomolecules
 Cobalt found in vitamin B12
 Transition metals are in their ionic form and in a variety of oxidation states
 Oxidation state: number of electrons lost (LEO THE LION SAYS GER)
 Remember: electrons are lost from 4s before 3d
 Electro negativity: power of nucleus to attract electrons
 It is too difficult to remove d electrons as they become lower in energy as
the nuclear charge increases
 CoCl3 + 6ammonia = a yellow compound
 But if both are stable compounds why would they form a complex?
 Also, CoCl3 with 5 ammonia, or 4 ammonia = purple, green or violet
compounds
 Coordination compound: transition metal (lewis acid) with its attached
ligands (lewis base)
 Lewis aid accepts electrons (CoCl3, lewis base donates electrons
 Metal-ligand bond  bond between lewis acid and lewis base
 Write down electron configurations and see which electrons are fair, then
see if metal ligands will create a stable molecule
 Coordination number = number of coordinate covalent bonds ( or number
of ligands DIRECTLY bound to the central transition metal ion)
 [Co(NH3)6]Cl3
 Inside the bracket is ligands bound to central ion (6 in this case)
 Outside the bracket is the counter ions that do NOT count towards
coordination number
 Coordination number varies from 2 to 8 but depends on a number of
factors including electron configuration of the transition metal ion

CHEM 110 LECTURE 3 nov 9th 2009
 Neutral ligands: H20, NH3, CO, NO (aqua, amine, carbonyl, nitrosyl)
 For eg. NH3 uses its lone pair of electrons to bind to a transition metal
 Proper names and terminology – with ligands that end with ide, you must
remove the ide and add “o”  Flouro, chloro, bromo etc.
 Bidentate ( two teeth ligand) has two sites (two electron pairs) for
attachment and so can form two bonds with the metal ion
 Bi and poly-dendate ligands surround the metal and act as a clawand form
very stable complex ions with most metal ions
o Used as a scavenger to remove toxic heavy metals from the body
CH 24.3 NOMENCLATURE FOR COORDINATION COMPONDS
 Most comlex ions are charged
o Name cation first, anion second
o Name ligands first in alphabetic order, and then metal center last
 The oxidation state of the metal is given with ROMAN NUMERALS
 Charge on complex ion – charge on ligands = oxidation state charge
 NAMING METAL COMPLEXES ON SLIDE LEARN THAT
CHEM 110 LECTURE nov 11th 2009
 Isomers are molecules with the same composition but different
arrangement of atons
 Stereoisomers differ in arrangement of ligands about metal
o Geometric isomers
o Optical isomers
 Structural isomers differ in atoms bonded to metal
o Cooridination isomers
o Linkage isomers
- Coordination isomers: compounds in which the composition within the
coordination sphere
- Where the metal is placed affects whether it is a coordination isomer
- First must determine oxidation state of metal in anion and cation
- Name cation first then anion, then starting with ligands within each
- Ionization isomers are compounds in which the counter ion is different 
differences in coordination sphere and in the counter ion (so one has a
different anion in the solution) e.g. [CO(NH3)5Cl]Br and [CO(NH3)5Br]Cl
- Linkage isomers are compounds in which the donor atom of the ligands is
different  how the ligands are linked to the transition metal ion e.g.
thiocyaniate ion where the ligand can bind to sulfur OR nitrogen
- However linkage exists only when there is a choice in the ligands, (if ligand
can bond to a metal atom in more than one way)
- Geometrical isomers differs in the relative orientation of ligands around the
metal (cis  ligands beside each other, trans  opposite each other)
- Cis and trans have different properties e.g. cis-platin is an anti cancer drug,
but trans-platin has no cancer fighting properties
- Because of different spatial arrangements in ligands, this leads to different
physical properties such as colours, melting point, etc.
- Optical isomers (relate to light)  way they react to light is different,
however compounds are same molecular formula, but are
nonsuperimposable mirror images
CHEM LECTURE NOV 27TH 2009
- Graphite sheets held together by van der waals forces which explains the
delocalized electrons free to move anywhere, which means graphite can
easily conduct electricity
- However in a diamond, all the electrons are tied up which means its an
insulator
- Sheets of graphite are held together by weak van der waals forces which
explains why they can slip and slide on top of each other (explaining its
properties and uses as a solid lubricant)
- Differences in properties of diamond vs graphite are based on their
intramolecular forces
- Simulating red giant star conditions in a lab: includes the vaporization of
carbon from solid graphite using a mass spectrometer to look at mass of
carbon (crucial mass in this experiment was 720)
- Discovered that mass came from C60, called a buckyball
- Fullerenes are large carbon-cage molecules (buckyball) but others are C70,
C76, C84
- Fullerenes exist in interstellar dust (space between stars)
- Buckyballs have the ability to block HIV virus from attacking healthy cells
under certain conditions
- Carbon nanotubes: molecular scale tubes of graphitic carbon
o Bonding is sp2 similar with each atom joined to three neighbours as
in graphite, which can therefore be considered rolled up grapheme
sheets
o Stiff and strong fibers and have strong electronic properties
o Ideal for reinforced composites, nanoelectromechanical systems
- Ionic solids: made up of oppositely charged ions that interact by coulombic
forces between them
- A crystal is defined as a lattice describing the way ions are repeated in
space
- A unit cell is a subset of the lattice containing enough information to
completely understand lattice
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