Download Coordination Chemistry

Coordination Chemistry
Transition metal
compounds
Transition metals
have multiple
charges because
of the d orbitals.
This also gives them lots of color
and bonding capabilities.
Figure 23.5 Aqueous oxoanions of transition elements.
One of the most characteristic
chemical properties of these
elements is the occurrence of
multiple oxidation states.
Mn2+
MnO42−
MnO4−
MnO4−
VO43−
Cr2O72−
Figure 23.6
Colors of representative compounds of the Period 4 transition metals.
sodium chromate
Titanium(IV) oxide
scandium oxide
vanadyl sulfate
dihydrate
nickel(II) nitrate
hexahydrate
potassium
ferricyanide
manganese(II)
chloride
tetrahydrate
cobalt(II)
chloride
hexahydrate
zinc sulfate
heptahydrate
copper(II)
sulfate
pentahydrate
[Co(NH3)4Cl2]Cl
 Complex ion: central metal
atom bonded to a group of
metals or ions (most are
charged)
 Ligands: neutral molecule or
ion having a lone pair of
electrons that forms
coordinate covalent bond to
the metal ion
 Counter ion: anion or cation
needed to make the complex
ion neutral
Werner’s Theory
Alfred Werner suggested in
1893 that metal ions exhibit
what he called primary and
secondary valences.
 Primary valences were the
oxidation number for the metal
(+3 on the cobalt at the right).
 Secondary valences were the
coordination number, the number
of atoms directly bonded to the
metal (6 in the complex at the
right).
Names of Coordination Compounds
Rules for naming complexes:
1. The cation is named before the anion.
2. Within the complex ion, the ligands are named, in alphabetical
order, before the metal ion. Prefixes do not affect order.
3. Neutral ligands generally have the molecule name, but there are a
few exceptions. Anionic ligands drop the -ide and add -o after the
root name.
4. A numerical prefix indicates the number of ligands of a particular
type.
5. The oxidation state of the central metal ion is given by a Roman
numeral (in parentheses) only if the metal ion is variable.
6. If the complex ion is an anion we drop the ending of the metal
name and add -ate.
Nomenclature:
1. Determine oxidation # of metal.
2. Ligands are named first,
alphabetically with prefixes:
mono-, di-, tri-, tetra-, penta-,
hexa-. Prefixes do not affect
order.
3. Anion ligands = root + o
4. First name ends with metal +
variable charge (roman #s)
5. Second name = counter
ions/anion **anion use Latin
names
Writing Names and Formulas of Coordination
Compounds
(a) What is the systematic name of Na3[AlF6]?
(b) What is the systematic name of [Co(en)2Cl2]NO3?
(c) What is the formula of tetraaminebromochloroplatinum(IV)
chloride?
(d) What is the formula of hexaaminecobalt(III) tetrachloroferrate(III)?