. Stability of metal complexes: The stability of coordination complexes can be interpreted in two different ways. The first one is thermodynamic stability and second one is kinetic stability. Thermodynamic stability of a coordination complex refers to the free energy change (∆G) of a complex formation reaction.
Kinetic stability of a coordination complex refers to the ligand substitution. In some cases, complexes can undergo rapid ligand substitution; such complexes are called labile complexes. However, some complexes undergo ligand substitution very slowly (or sometimes no substitution), such complexes are called inert complexes. Stability constant:( β ) The stability of a coordination complex is a measure of its resistance to the replacement of one ligand by another.
The stability of a complex refers to the degree of association between two species involved in an equilibrium. Let us consider the following complex formation reaction Cu NH Cu NH + ⇀ ↽ β=