Question

What are the correct oxidation state, coordination number, configuration, magnetic character and magnetic moment of $K_4\left[Mn\right(CN{)}_6]$?

• A. O.S +6, - C.N 6, - Configuration $t_{2g}^5$, - Magnetic Charater Diamagnetic, - Magentic Moment 0
• B. O.S +4, - C.N 6, - Configuration $t_{2g}^5{e}_g^1$, - Magnetic Charater Paramagnetic, - Magentic Moment 1.732 B.M
• C. O.S +2, - C.N 6, - Configuration $t_{2g}^5$, - Magnetic Charater Paramagnetic, - Magentic Moment 1.732 B.M
• D. O.S +4, - C.N 6, - Configuration $t_{2g}^5{e}_g^2$, - Magnetic Charater Diamagnetic, - Magentic Moment 0

Answer 1

The correct option is C O.S +2, - C.N 6, - Configuration $t_{2g}^5$, - Magnetic Charater Paramagnetic, - Magentic Moment 1.732 B.M

$K_4\left[Mn\right(CN{)}_6]\Rightarrow [Mn(CN{)}_6{]}^{4-}$

$n-6\left(1\right)=-4$

$n=6-4=2$

$n=2$

so, $O.S=+2$

$M{n}^{2+}\Rightarrow \left[Ar\right]3d^5$

As $C{N}^{-}$ is strong field ligand Pairing occur in $t_{2g}$

$=E.C=t_{2g}^5{e}_g^o$

The co-ordination number $=6$

It has i unpaired electrons

So paramagnetic.

Magneic Moment $=\sqrt{1(1+2)}=\sqrt{3}=1.732B.M$