Question

The value of 'spin only' magnetic moment for one of the following configuration is $2.84BM$. The correct one is

• A. $d^4$ (in strong field ligand)
• B. $d^2$ (in weak field ligand)
• C. $d^3$ (in weak as well as in strong field ligand)
• D. $d^5$ (in strong field ligand)

Answer 1

Answer: (B)

$d^2$ (in weak field ligand)

The spin only magnetic moment is given by the formula ${\mu }_{eff}=\sqrt{n(n+2)}B.M.$

For two unpaired electrons, the expression becomes ${\mu }_{eff}=\sqrt{2(2+2)}B.M.=\sqrt{8}=2.84B.M.$.

Thus the electronic configuration is $d^2$.

It is irrespective of the strength of the ligand.

Hence, the correct option is B.