Question

What is the magnetic moment of $Fe^{3+}$ ion in $[Fe(CN)_6]^{3-}$ ?

• A. $1.73\,BM$
• B. $5.9\,BM$
• C. $Diamagnetic$
• D. None of these

Answer 1

Answer: (A)

$1.73\,BM$

Answer 2

$Fe^{3+}=[Ar] 3d^{5}$
$(\because CN^{-}$ being a strong field ligand causes pairing)
$\therefore$ Magnetic moment, $\mu = \sqrt{n(n+2)} BM$
(where, $n$ = number of unpaired electrons)
$=\sqrt{1 (1+2)} =\sqrt{3}$
$=1.73\,BM$