Question

What will be the geometry and magnetic moment of the complex $ [NiCl_4]^{2-} $ ?

• A. Tetrahedral and $ 3.87 \,B.M $
• B. Tetrahedral and $ 2.82 \,B.M $
• C. Square planar and $ 2.82\, B.M $
• D. Square planar and $ 4.89\, B.M $

Answer 1

Answer: (B)

$Ni^{2+} \Rightarrow [Ar] 3d^{8}$
In a weak field ligand, pairing does not take place
So, $[NiCl_{4}]^{2-} : [Ar] $
Thus, geometry is tetrahedral with two unpaired electrons
Magnetic moment $=\sqrt{n\left(n+2\right)}$
$\sqrt{2\left(4\right)}$
$=2.82 \, B.M.$