Chemistry - Coordination Chemistry Question with Solution | TestHub

Tetrahedral geometry typically arises when the central metal ion has an sp³ hybridization. This is common for d¹⁰ systems or d⁸ systems with weak field ligands.

A. Both $[\mathrm{FeC}{\mathrm{l}}_4{]}^{-}$ (Fe³⁺, d⁵, weak field) and $[\mathrm{Fe}(\mathrm{CO}{)}_4{]}^{2-}$ (Fe⁰, d⁸, strong field, but CO is a strong $\pi$-acceptor leading to sp³ hybridization) are tetrahedral.

B. Both $[\mathrm{Co}(\mathrm{CO}{)}_4{]}^{-}$ (Co⁻, d¹⁰) and $[\mathrm{CoC}{\mathrm{l}}_4{]}^{2-}$ (Co²⁺, d⁷, weak field) are tetrahedral.

C. $[\mathrm{Ni}(\mathrm{CO}{)}_4]$ (Ni⁰, d¹⁰) is tetrahedral, but $[\mathrm{Ni}(\mathrm{CN}{)}_4{]}^{2-}$ (Ni²⁺, d⁸, strong field) is square planar.

D. Both $[\mathrm{Cu}(\mathrm{py}{)}_4{]}^{+}$ (Cu⁺, d¹⁰) and $[\mathrm{Cu}(\mathrm{CN}{)}_4{]}^{3-}$ (Cu⁺, d¹⁰) are tetrahedral.