Question

The complex showing a spin-magnetic moment of 2.82 B.M. is :

• A. Ni(CO)${}_4$
• B. [NiCl${}_4$]${}^{2-}$
• C. Ni(PPh${}_3$)${}_4$
• D. [Ni(CN)${}_4$]${}^{2-}$

Answer 1

Answer: (B)

[NiCl${}_4$]${}^{2-}$

$\left[Ni\right(Cl{)}_4{]}^{2-}$

The oxidation state of $Ni$ is $+2.$

The atomic number of nickel is $28.$

Ni = $\left[Ar\right]3d^{8}4s^2$

$N{i}^{2+}=\left[Ar\right]3d^8$

$s{p}^3$-Hybridization, tetrahedral shape.

There are two unpaired electrons.

Spin magnetic moment = $\sqrt{n(n+2)}=\sqrt{2(2+2)}=\sqrt{8}$ BM

$\approx 2.82$ BM

So, the correct option is $B$