Question

In octahedral complex, the value of the 'spin only' magnetic moment for one of the following configurations is $2.84 BM$. The correct one is

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

Answer 1

Answer: (A)

Spin only magnetic moment $=\sqrt{n(n+2)}$

Where $n=$ number of unpaired electrons.

$\sqrt{n(n+2)}=2.84 BM$ (given)

Hence, $n=2$

In octahedral complex a strong field ligand results in a low spin complex.

Thus, $d^{4}$ configuration has two unpaired electrons.