Question

The correct order of magnetic moments of the given compounds is (spin only values in $B.M$.)
(Atomic nos.: $Mn =25, Fe =26, Co =27)$

• A. $\left[ MnCl _{4}\right]^{2-}>\left[ CoCl _{4}\right]^{2-}>\left[ Fe ( CN )_{6}\right]^{4-}$
• B. $\left[ MnCl _{4}\right]^{2-}>\left[ Fe ( CN )_{6}\right]^{4-}>\left[ CoCl _{4}\right]^{2-}$
• C. $\left[ Fe ( CN )_{6}\right]^{4-}>\left[ MnCl _{4}\right]^{2-}>\left[ CoCl _{4}\right]^{2-}$
• D. $\left[ Fe ( CN )_{6}\right]^{4-}>\left[ CoCl _{4}\right]^{2-}>\left[ MnCl _{4}\right]^{2-}$

Answer 1

Answer: (A)

Number of unpaired electrons $=0$

Magnetic moment $=n \sqrt{n+2}$

where $n=$ number of unpaired electrons.

i.e. greater the number of unpaired electrons, greater will be the paramagnetic character.