Chemistry - Coordination Chemistry Question with Solution | TestHub

The selected region shows a chemistry problem asking for complexes that are tetrahedral and diamagnetic. Here is the solution:

$[Ni(CO{)}_4]$ (Option A): $Ni$ is in the $0$ oxidation state ($3d^{8}4s^2$). The strong field ligand $CO$ causes all $10$ electrons to pair in the $3d$ subshell, resulting in $s{p}^3$ hybridization (tetrahedral) and no unpaired electrons (diamagnetic).

$Fe(CO{)}_5$ (Option B): This complex has a coordination number of $5$, giving it a trigonal bipyramidal structure, not tetrahedral.

$[CoC{l}_4{]}^{2-}$ (Option C): $C{o}^{2+}$ ($3d^7$) with weak field $C{l}^{-}$ ligands is $s{p}^3$ (tetrahedral), but it has three unpaired electrons, making it paramagnetic.

$[Ni(CN{)}_4{]}^{4-}$ (Option D): $Ni$ is in the $0$ oxidation state. Similar to $[Ni(CO{)}_4]$, the strong field $C{N}^{-}$ causes pairing into a $3d^{10}$ configuration, resulting in $s{p}^3$ hybridization (tetrahedral) and a diamagnetic nature.