Chemistry - Coordination Chemistry Question with Solution | TestHub

Platinum ($P{t}^{2+}$) belongs to the $5d$ transition series and has a $5d^8$ electronic configuration.

Due to the high crystal field splitting energy of $5d$ elements, all ligands (even weak ones like $C{l}^{-}$) force electron pairing.

This leaves one internal $d$-orbital vacant, leading to $ds{p}^2$ hybridization and a square planar geometry. Conversely, the other complexes ($[Ni(CN{)}_4{]}^{4-}$, $[Ni(CO{)}_4]$, and $[Cd(CN{)}_4{]}^{2-}$) form filled $d^{10}$ configurations, resulting in $s{p}^3$ tetrahedral structures.