notes ch22 Coordination Compounds

Chapter 22
20.3 Coordination
Metallic salts are surrounded by water
when they dissolve.
 Dipoles in water are attracted to the
Complexes and Ligands
Ions in which a metal ion and either
water or ammonia molecules
compose a unit are examples of
coordination compounds or complex
 Compounds containing a complex ion
as part of their structure are called
coordination compounds.
Complexes and Ligands
You can write a complex ion as a
hydrate, or (more current) as a single
NiCl2•6H2O OR [Ni(H2O)6]Cl2
Complexes and Ligands
All coordiation complexes contain a
metal atom/ion as the central part of
the structure.
 Ligands are molecules or ions bonded
to the metal.
the number of ligands attached to the
metal defines the coordination number
Complexes and Ligands
Ligands are usually either neutral
molecules or anions. Must have a
lone pair of electrons (Lewis base)!
The attachment is called a coordinate
covalent bond.
 Net charge is the sum of the charges
on the metal and its attached groups.
Formulas of Coordination
Problem: Give the formulas of the following
coordination complex:
A Ni2+ ion is bound to two water
molecules and two bidentate oxalate
This complex ion is constructed from two
neutral H2O molecules, two C2O42- ions, and
one Ni2+ ion, so the net charge is 2-. The
formula is [Ni(C2O4)2(H2O)2]2-.
Practice Problem
What is the formula of a complex ion
composed of one Co3+ ion, three
ammonia molecules, and three Clions?
 Determine the metal’s oxidation
number and coordination number in
(a) K3[Co(NO2)6]
(b) Mn(NH3)4Cl2
Naming Coordination
Name the cation first and then the
 For a complex ion, name the ligands
first, in alphabetical order (disregard
prefix), followed by the name of the
Naming Coordination
Ligands and their names:
 If anion is –ite or –ate, the final e is
changed to o.
 If anion ends in –ide, the ending is
changed to o.
 If neutral molecule, its common name
is used except for water (aqua),
ammonia (ammine), and CO
 Use prefixes as needed.
Naming Coordination
If the coordination complex is an
anion, the suffix –ate is added to the
metal name.
 Following the name of the metal, the
oxidation number of the metal is given
as Roman numerals.
Practice Problem
Name the following coordination
 [Ni(H2O)6]SO4
 K[Pt(NH3)Cl3]
 K[CuCl2]
After reading Section 22.3, you should
be able to do the following:
 P.1055 (9-18)