1. Structural Isomerism:
a) Ionization Isomerism: It occurs when the ligands in the complex can be exchanged with the anions present outside the coordination sphere.
b) Hydrated isomerism: it occurs when different number of water molecules are present inside and outside the coordination sphere.
c) Linkage Isomerism: Occurs in ambidentate ligands.
d) Coordination Isomerism: It occurs when both cations and anions are complexes in such cases the ligand or the central metal atom or both can be exchanged.