Explanation Ionisation isomerism refers to a form of isomerism in which compounds containing the same composition give different ions when dissolved in a solution. The cause for such a form of isomerism to exist is the presence of a counter ion in a complex salt which has the capability to behave as a ligand itself. In such a case, the counter ion displaces the ligand and becomes a ligand itself. The ligand, in turn, becomes the counter ion.
