Question

Among the following the species that is both tetrahedral and diamagnetic is

• A. $[NiC{l}_4{]}^{2-}$
• B. $[Ni(CN{)}_4{]}^{2-}$
• C. $Ni(CO{)}_4$
• D. $[Ni(H_{2}O{)}_6{]}^{2+}$

Answer 1

Answer: (C)

In $Ni(CO{)}_4,Ni$, is in $0$ oxidation number thus,
its electronic configuration is $3d^{8}4s^2$.

As $CO$ is a strong field ligand and pairing of electrons occurs thus its configuration becomes$3d^{10}4s^0$.

As $Ni(CO{)}_4$ has $s{p}^3$ -hybridisation, so its geometry will be tetrahedral.
Also, all the electrons are paired, so it is diamagnetic in nature.