Question

Explain on the basis of valence bond theory that $\left[Ni\right(CN{)}_4{]}^{2-}$ is a low spin complex ion.

Answer 1

In the complex $\left[Ni\right(CN{)}_4{]}^{2-}$, the central Ni metal has $+2$ oxidation state with outer electronic configuration $3d^8$. One $3d$, one $4s$ and two $4p$ orbitals undergo $ds{p}^2$ hybridisation. Since, inner $d$ orbital is used in the hybridsation, the complex is inner orbital or low spin or spin paired complex.