Question

Type of isomerism exhibited by $\left[Cr\right(NCS\left)\right(N{H}_3{)}_5\left]\right[ZnC{l}_4]$ is:

• A. coordination isomerism
• B. linkage isomerism
• C. ionization isomerism
• D. both coordination and linkage isomerism

Answer 1

The correct option is D both coordination and linkage isomerism

Linkage isomers arise when an ambidentate ligand can coordinate to a metal cation through either of the two different donor atoms.
In given complex -SCN is an ambidentate ligand.
Hence, the possible linkage isomers are,
$\left[Cr\right(NCS\left)\right(N{H}_3{)}_5\left]\right[ZnC{l}_4]$ and $\left[Cr\right(SCN\left)\right(N{H}_3{)}_5\left]\right[ZnC{l}_4]$

In complexes when the cation and anion both are complex ions, there may be exchange of ligands between these two complex ions resulting in coordination isomers.
Thus, Cl and NCS can change coordinate sphere to exhibit coordination isomers.
Thus, the possible coordination isomers are
$\left[Cr\right(NCS\left)\right(N{H}_3{)}_5\left]\right[ZnC{l}_4]$ and $\left[Cr\right(N{H}_3{)}_{5}Cl\left]\right[Zn\left(NCS\right)C{l}_3]$

Hence, option (d) is correct.