Coordination Isomerism
Isomerism in compounds containing both a complex cation and a complex anion, where ligands are distributed differently between them.
Unit
Dimensionless
In depth
Both metals are complexed, so exchanging ligand sets between the cation and the anion gives compounds of identical overall formula but different composition in each sphere. The isomers differ in colour, magnetic behaviour and spectra.
Examples in the real world
[Co(NH₃)₆][Cr(CN)₆] and [Cr(NH₃)₆][Co(CN)₆] share a formula but have their ligands swapped.