Question

The molecular shape of Ni(CO)4 is not the same as [Ni(CN)4]2-

Answer 1

[Ni(CN)4]2- is square planar because CN is strong ligand it in the presence of this ligand electrons are pair up in 3d orbitals.so inner orbital comples it is undergo dsp2 hybridization so it is in square panar geometry while [Ni(co)4] it is undergo sp3 hybridization so it has tetrahydral geometry .

Answer 2

The molecular shape of $[Ni(CO)_4]$ is tetrahedral and $[Ni(CN)_4]^{2-}$ is square planar.

• $[Ni(CO)_4]$ has CO which is a weak field ligands and Ni exist in a 0 oxidation state so, it undergoes $sp^3$ hybridization and forms a tetrahedral structure.
• $[Ni(CN)_4]^{2-}$ has CN which is a strong field ligands and Ni exists in a +2 oxidation state. Thus the strong CN ligands make the pairing of electrons in the 3d orbital so, it undergoes $dsp^2$ hybridization and forms a square planar structure.