Question

For the octahedral complexes of $F{e}^{3+}$ in $SC{N}^{-}$ (thiocyanato-S) and in $C{N}^{-}$ ligand environments, the difference between the spin-only magnetic moments in Bohr Magneton (when approximated to the nearest integer) is -
[Atomic number of Fe = 26]

Answer 1

Answer: 4

$F{e}^{+3}+SC{N}^{-}\to {\left[Fe{\left(SCN\right)}_6\right]}^{3-}$
$F{e}^{+3}\Rightarrow \left[Ar\right]3d^5$
Number of unpaired electrons $=5$
$\mu =5.9$
$F{e}^{+3}+C{N}^{-}\to {\left[Fe{\left(CN\right)}_6\right]}^{3-}$
$F{e}^{+3}=\left[Ar\right]3d^5$
Number of unpaired electrons $=1$
$\mu =1.732$
Difference $=5.91-1.73=4.18$
$\simeq 4$