Question

Which complex is more stable in each pair?

(a) $\left[Ni\right(CN{)}_4{]}^{2-}$ , $\left[Pt\right(CN{)}_4{]}^{2-}$.

Answer 1

$\left[Pt\right(CN{)}_4{]}^{2-}$ has $Pt$ in $+2$ oxidation state. It forms a square planar structure with $ds{p}^2$ hybridisation.

$C{N}^{-}$ bring a strong field ligand causes pairing of unpaired electrons. Hence, $\left[Ni\right(CN)4{]}^{-2}$ is more stable than $Pt(CN{)}_4{]}^{2-}$ .