Question

What is the value of spin only magnetic moment of anionic and cationic part of complex ${\left[Fe{\left(H_{2}O\right)}_6\right]}_2$ $\left[Fe{\left(CN\right)}_6\right]$?

• A. $4.9$ B.M and Zero
• B. Zero and $4.9$ B.M
• C. $2.9$ B.M and $0$
• D. $0$ and $2.9$ B.M

Answer 1

The correct option is B Zero and $4.9$ B.M

${\left[Fe{\left(CN\right)}_6\right]}^{-4}$

${Fe}^{+2}⟶3d^6$

${CN}^{-}\to$ S.F.L

$t_{2g}^{2,2,2}$ ${eg}^{0,0}$

No. of unpaired $e^{-}=0$

$B.M=0$

${\left[Fe{\left(H_{2}O\right)}_6\right]}^{+2}$

${Fe}^{+2}⟶3d^6$

$H_{2}O\to$W.FL

$t_{2g}^{2,1,1}$ ${eg}^{1,1}$

No. of unpaired electrons $e^{-}=4$

$\mu =\sqrt{4\times 6}=\sqrt{24}B.M=4.9B.M$