Question

Magnetic moment of [MnCl4]^2– is 5.92 BM. Explain giving reason.

Answer 1

In the compound, the overall charge on the coordination sphere is -2, the charge by the 4 Cl ligands is -4, so the Oxidation no. of Central Metal Atom Mn will be +2.
Mn(25) =
$3d ^{5} \: 4s^{2}$
Now +2 charge on Mn means only
$3d^{5}$
All these five electrons will be unpaired.

Now Magnetic Moment =
$\sqrt{n(n + 2)}$
where n=no. of unpaired electrons.
Here, n=5
So,
$\sqrt{5(5 + 2)} \\ = \sqrt{5 \times 7} \\ = \sqrt{35} \\ = 5.916 \:$
M.M. = 5.92 B.M.