This section will include:
A substitution reaction is a reaction in which one ligand is driven out of a d-metal complex and is replaced by another ligand. The incoming group is called the entering group (Y) and the displaced ligand is called the leaving group (X). A substitution reaction can then be shown as a Lewis acid displacement reaction like that shown below.
Both the thermodynamics and the kinetics of complex formation lead to an understanding of the reaction of complexes. Before we can fully understand substitution reactions, first the difference between kinetics and thermodynamics must be clarified.