Question

What are coordination isomers? Give an example.

Answer 1

Coordination isomers

• Coordination isomers are two or more coordination compounds in which the composition within the coordination sphere.
• The interchange of ligands between anionic and cationic entities of different metal ions present in complex causes this type of isomerism.

Example of Coordination isomers

• An example of this type of isomer is $[\mathrm{Co}{({\mathrm{NH}}_3)}_6][\mathrm{Cr}{\left(\mathrm{CN}\right)}_6]$.
• In the above coordination compound, cyanide $\left({\mathrm{CN}}^{–}\right)$ ligands is attached to ${\mathrm{Cr}}^{3+}$, and ammonia $\left({\mathrm{NH}}_3\right)$ ligands are attached to ${\mathrm{Co}}^{3+}$.
• In its coordination isomer $[\mathrm{Co}{\left(\mathrm{CN}\right)}_6][\mathrm{Cr}{({\mathrm{NH}}_3)}_6]$, the $\left({\mathrm{NH}}_3\right)$ ligands are bound to ${\mathrm{Cr}}^{3+}$ and the cyanide $\left({\mathrm{CN}}^{–}\right)$ ligands to ${\mathrm{Co}}^{3+}$.