Chemistry - Coordination Chemistry Question with Solution | TestHub

Ni²⁺ = 3d⁸

With excess CN⁻, a strong-field ligand causes pairing of 3d electrons, leaving one d orbital vacant. Hence, [Ni(CN)₄]²⁻ is square planar with dsp² hybridization.

With excess Cl⁻, a weak-field ligand does not cause pairing. Hence, [NiCl₄]²⁻ is tetrahedral with sp³ hybridization.

$$\boxed{A=ds{p}^2,B=s{p}^3}$$