Q. Which of the following species will be diamagnetic?
A) $\left\lbrack Fe(CN)_{6} \right\rbrack^{4 -}$
B) $\left\lbrack {FeF}_{6} \right\rbrack^{3 -}$
C) $\left\lbrack Co\left( C_{2}O_{4} \right)_{3} \right\rbrack^{3 -}$
D) $\left\lbrack {CoF}_{6} \right\rbrack^{3 -}$
Explanation
(a)
$\left\lbrack Fe(CN)_{6} \right\rbrack^{4 -} \rightarrow {Fe}^{2 +} \rightarrow$
(Strong field)
$1s^{2},2s^{2}2p^{6},3s^{2}3p^{6}3d^{6}$
[image:9_image283.emf]
$CN^{-}$ is strong field ligand, it cause pairing while $C_{2}O_{4}^{2 -}$ and $F^{-}$ are weak field ligands and don’t causes pairing.
Hence, $\left\lbrack Fe(CN)_{6} \right\rbrack^{4 -}$ due to the absence of unpaired electrons is diamagnetic.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.