What type of isomerism is exhibited by coordination compounds that have the same composition but differ in the ligand attached directly to the metal ion versus being outside the coordination sphere as a counter-ion?

💡 Solution & Explanation

Ionization isomerism occurs when coordination compounds share the same molecular formula but yield different ions in solution because an anionic ligand and a counter-ion exchange places. Alternative choices like linkage isomerism involve ambidentate ligands bonding through different donor atoms, while hydrate isomerism involves water molecules shifting between the coordination sphere and the solvent sphere. This concept helps determine the structural formulae of complex salts during qualitative analysis in inorganic chemistry.