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)

Tetrahedral and $2.82 \,B.M$

Answer 2

$Ni^{2+} \Rightarrow [Ar] 3d^{8}$
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 $=\sqrt{n\left(n+2\right)}$
$\sqrt{2\left(4\right)}$
$=2.82 \, B.M.$