Question

Which one of the following has the lowest value of paramagnetic behavior?

• A. $\left[Cr\right(CN{)}_6{]}^{3-}$
• B. $\left[Mn\right(CN{)}_6{]}^{3-}$
• C. $\left[Fe\right(CN{)}_6{]}^{3-}$
• D. $\left[Co\right(CN{)}_6{]}^{3-}$

Answer 1

The correct option is A $\left[Cr\right(CN{)}_6{]}^{3-}$

As we know,
magnetic moment
$\mu =\sqrt{n(n+2)}$ BM
n = no of unpaired electron so
higher no of unpaired electron will have higher moment.
$\left[Co\right(CN{)}_6{]}^{3-}$
+3 n = 4
$\left[Fe\right(CN{)}_6{]}^{3-}$
+3 n = 5
$\left[Mn\right(CN{)}_6{]}^{3-}$
+3 n = 4
$\left[Cr\right(CN{)}_6{]}^{3-}$
+3 n = 3
so it have lowest magnetic moment and shows least paramagnetic behaviour.