Introduction

Characteristics of Coordination Complexes

The transition metal atom can often exist in more than one oxidation state.
Many coordination complexes are colored.
Many coordination complexes are paramagnetic.
- paramagnetic substance: a substance that contains unpaired electrons; paramagnetic substances tend to move into a magnetic field
- diamagnetic substance: a substance that contains no unpaired electrons; diamagnetic substances tend to move out of a magnetic field

The Crystal Field Model

The crystal field model concentrates on the splitting of the d orbitals of the transition metal atom into groups as a result of electrostatic interactions between the ligands and the electrons in the unhybridized orbitals of the transition metal atom. The model can be used to understand, interpret and predict the magnetic behavior, colors and some structures of coordination complexes.

Note that the crystal field model does not explain the bonding in coordination complexes; it describes only behavior that can be attributed to electrons on the transition metal atom in the coordination complex.