Question

How many of the following do not have square planar geometry ?
${\left[FeC{l}_4\right]}^{2-},{\left[NiC{l}_4\right]}^{2-},{\left[PtC{l}_4\right]}^{2-},{\left[CoC{l}_4\right]}^{2-}$

Answer 1

Answer: 3

${\left(\left[Fe{\left(Cl\right)}_4\right]\right)}^{2-}$ has $F{e}^{+2}$ oxidation number with $\left[Ar\right]3d^6$ electronic configuration and as $C{l}^{-}$ is weak field ligand hence its geometry will be tetrahedral with $s{p}^3$ hybridisation.
. ${\left(\left[Ni{\left(Cl\right)}_4\right]\right)}^{2-}$ has $N{i}^{+2}$ oxidation number with $\left[Ar\right]3d^8$ electronic configuration and as $C{l}^{-}$ is weak field ligand hence its geometry will be tetrahedral with $s{p}^3$ hyridisation.
${\left(\left[Co{\left(Cl\right)}_4\right]\right)}^{2-}$ has $C{o}^{+2}$ oxidation number with $\left[Ar\right]3d^7$ electronic configuration and as $C{l}^{-}$ is weak field ligand hence its geometry will be tetrahedral with $s{p}^3$ hybridisation.
While exceptionally ${\left[PtC{l}_4\right]}^{2-}$ has square planar structure with $ds{p}^2$ hybridisation.