Question

Give an example of a compound which can form a linkage isomer.

Answer 1

Linkage isomerism:-

1. Coordination compounds that have the same chemical composition but differ in their properties, due to their different modes of attachment of an ambient ligand to the central atom through different sites are called linkage isomers.
2. And this process of linkage is known as linkage isomerism.
3. An example of linkage isomerism is $\left[\mathrm{CO}{\left({\mathrm{NH}}_3\right)}_5\right(\mathrm{ONO}\left)\right]{\mathrm{Cl}}_2$(pentaamminenitro-O-cobalt(III) chloride) and $\left[\mathrm{CO}{\left({\mathrm{NH}}_3\right)}_5{\mathrm{NO}}_2\right]{\mathrm{Cl}}_2$(pentaamminenitro-N-cobalt(III) chloride)
4. In $\left[\mathrm{CO}{\left({\mathrm{NH}}_3\right)}_5\right(\mathrm{ONO}\left)\right]{\mathrm{Cl}}_2$ the compound is linked via an oxygen atom, but in $\left[\mathrm{CO}{\left({\mathrm{NH}}_3\right)}_5{\mathrm{NO}}_2\right]{\mathrm{Cl}}_2$ the compound is linked via nitrogen-atom.
5. $\left[\mathrm{CO}{\left({\mathrm{NH}}_3\right)}_5\right(\mathrm{ONO}\left)\right]{\mathrm{Cl}}_2$(pentaamminenitro-O-cobalt(III) chloride) is a red-coloured complex and $\left[\mathrm{CO}{\left({\mathrm{NH}}_3\right)}_5{\mathrm{NO}}_2\right]{\mathrm{Cl}}_2$(pentaamminenitro-N-cobalt(III) chloride) is a yellow-coloured complex.

Therefore, an example of linkage isomerism is $\left[\mathrm{CO}{\left({\mathrm{NH}}_3\right)}_5\right(\mathrm{ONO}\left)\right]{\mathrm{Cl}}_2$ and $\left[\mathrm{CO}{\left({\mathrm{NH}}_3\right)}_5{\mathrm{NO}}_2\right]{\mathrm{Cl}}_2$.