If Ni ^ 2 + is replaced by Pt ^ 2 + in the complex [ NiCl _ 2 Br _...

When${Ni}^{2 +}$ is replaced by${Pt}^{2 +}$ in the complex ${\left[{NiCl}_{2}{Br}_{2}\right]}^{2 -}$, the following properties are expected to be changed:

A. Geometry: Since ${Pt}^{2 +}$ and ${Ni}^{2 +}$ have different coordination preferences and atomic sizes, the replacement is likely to result in a change in the geometry of the complex. That is it changes to square planar.

B. Geometrical isomerism: If the replacement of ${Ni}^{2 +}$ with ${Pt}^{2 +}$ leads to a change in the ligand arrangement, it can result in the generation of cis and trans isomers.

C. Magnetic properties: ${\left[{PtCl}_{2}{Br}_{2}\right]}^{2 -}$ is diamagnetic.

Both the complex species are optically inactive.