Question

The complex $\left[Ni\right(CN{)}_4{]}^{2-}$ is:

• A. Tetrahedral and paramagnetic
• B. Tetrahedral and diamagnetic
• C. Square planar and paramagnetic
• D. Square planar and diamagnetic

Answer 1

The correct option is D Square planar and diamagnetic

Here Ni is in +2 oxidation state. So the electronic configuration of $Ni=\left[Ar\right]4s^{0}3d^8$. Now since $C{N}^{-}$ is a strong field ligand, it will pair up the electrons and will make it a diamagnetic complex.
Hybridisation of this complex will be $ds{p}^2$ and thus the shape of the complex is square planar.