Which kind of isomerism exists between [Co(NH₃)₆][Cr(CN)₆] and [Cr(NH₃)₆][Co(CN)₆]?

Coordination isomerism

Coordination isomerism: This type of isomerism arises from the interchange of ligands between cationic and anionic entities of different metal ions present in a complex. An example is provided by [Co(NH₃)₆][Cr(CN)₆], in which the NH₃ ligands are bound to Co³⁺ and the CN^– ligands to Cr³⁺. In its coordination isomer [Cr(NH₃)₆][Co(CN)₆], the NH₃ ligands are bound to Cr³⁺ and the CN^– ligands to Co³⁺.