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 $[\text{Co}(\text{NH}_3)_6][\text{Cr}(\text{CN})_6]$, in which the $\text{NH}_3$ ligands are bound to $\text{Co}^{3+}$ and the $\text{CN}^-$ ligands to $\text{Cr}^{3+}$. In its coordination isomer $[\text{Cr}(\text{NH}_3)_6][\text{Co}(\text{CN})_6]$, the $\text{NH}_3$ ligands are bound to $\text{Cr}^{3+}$ and the $\text{CN}^-$ ligands to $\text{Co}^{3+}$.