Question

The magnetic moment (spin only) of $[NiC{l}_4{]}^{2-}$ is

• A. $1.82$ BM
• B. $5.46$ BM
• C. $2.82$ BM
• D. $1.41$ BM

Answer 1

Answer: (C)

$[NiC{l}_4{]}^{2-}$: oxidation number of Ni, $x-4--2$
$\therefore x=+2,N{i}_{(28)}[Ar]3d^8,4s^2$

$s{p}^3$ hybrid orbitals, tetrahedralSince, $C{l}^{-}$ is a weak ligand, thus unpaired electrons are not paired. Lone pairs from $4C{l}^{-}$ are accommodated in four $s{p}^3$ hybrid orbitals.
n = unpaired electron = 2, paramagnetic Magnetic moment (spin only)
$=\sqrt{n\left(n+2\right)}BM=\sqrt{8}=2.828BM$