Question

The spin-only magnetic moment value for the complex ${\left[Co(CN{)}_6\right]}^{4-}$ is_______ $BM$. [At. no. of $Co=27$ ]

Answer 1

Answer: 2

${\left[Co(CN{)}_6\right]}^{4-}$
$x+6\times (-1)=-4$
$x=+2$
$C{o}^{2+}:[Ar]3d^7$
and $C{N}^{-}$is a strong field ligand which can pair electron of central atom.

It has one unpaired electron $(n)$ in $4d$-subshell.
So spin only magnetic moment $(\mu )=\sqrt{n(n+2)}$ B.M
where $n=$ number of unpaired electrons.
$\mu =\sqrt{3}$ B.M
$\mu =1.73BM$