1. Coordination Compounds
Complex Ions
Coordination Compounds

2. What are complex ions?
Metal Complexes: Central metal ion bonded to a group of surrounding molecules
Complex Ions: Metal ions with a charge
Coordination Compounds: Compounds containing metal complexes
Ligands: Molecules or ions that surround the metal ion in a complex

3. Development of Coordination Chemistry: Werner’s Theory
Establish the idea that metal ions exhibit both primary and secondary valences.
Primary valence is the oxidation state of the metal
Secondary valence is # of atoms directly bonded to the metal ion. Also called Coordination Number.
Coordination Sphere: Central metal and ligands bound to it
Write formula using brackets around coordination sphere

4. Naming Coordination Compounds
Cations before anions
Ligands before metal ions
Name ligands by adding an o to the root name of the anion. Ex: floro, chloro, hydroxo
For a neutral ligand use name of molecule
Use prefixes to denote number of ligands
Oxidation state of central atom designated with roman numerals
Name multiple ligands alphabetically
If the complex ion has a negative charge, the suffix – ate is added to the name of the metal

5. Examples of Names [Co(NH3)5Cl]Cl2 K3Fe(CN)6 [Fe(en)2(NO2)2]2SO4
Pentaamminechlorocobalt(III) chloride
K3Fe(CN)6
Potassium hexacyanoferrate(III)
[Fe(en)2(NO2)2]2SO4
diethylenediamminebisnitroiron(III) sulfate
Triamminebromoplatinum(II)chloride
[Pt(NH3)3Br] Cl
Potassium hexaflorocobalt(III)
K3[CoF6]

6. Metal-Ligand Bond: Example of Lewis acid and Lewis Base
Ligands have unshared pairs of electrons, function as Lewis base
Metal ions have empty valence orbitals, function as Lewis acid
Ag+(aq) + 2 N-H (aq)  (aq)
Formation of the metal ligand bond greatly affects the properties of the metal ion. Some insoluble will become soluble

7. Copper is not highly reactive, but it will slowly corrode in air forming basic copper sulfate
3 Cu(s) + 2 H2O(l) + SO2(g) + 2 O2(g)  Cu3(OH)4SO4
Basic copper sulfate
Ammonia complexes with copper turn the solution from light blue to much darker blue
Cu2+aq) + 2 NH3(aq)  Cu(NH3)42+
Insoluble silver chloride (AgCl) dissolved in ammonia solutions to produce a soluble complex
AgCl(s) + NH3  Ag(NH3)2+ + Cl-