Question

The spin only magnetic moment of $Fe$ in the complex $\left[Fe\right(CN{)}_6{]}^{3-}$ in BM is:

• A. 1.414 BM
• B. 1.73 BM
• C. 2.82 BM
• D. 2 BM

Answer 1

The correct option is B 1.73 BM

In $\left[Fe\right(CN{)}_6{]}^{3-}$, the oxidation state of $Fe$ is +3 and the configuration is $\left[Ar\right]3d^5$. As $C{N}^{-}$ is a strong field ligand, there will be the pairing of electrons and only 1 electron will be unpaired.
$\therefore n=1$
${\mu }_{\text{spin}}=\sqrt{n(n+2)}=\sqrt{1(1+2)}$
$=\sqrt{3}=1.732=1.73$BM