Chemistry Question on Isomerism in Coordination Compounds

Question

Specify the coordination number of cobalt in $\left[ Co ( CN )\left( H _{2} O \right)( en )_{2}\right]^{2+}$

Answer 1

Solution

Let oxidation number of Co be $x$ ; Oxidation number of $H _{2} O =0$
Oxidation number of $C N=-1$
Therefore $\left[ Co ( CN )\left( H _{2} O \right)(e n)^{2}\right]^{2}$
$\therefore x +2(0)-1=+2 x-1=+2=+3$
or 3 Hence, coordination number of $Co$ is $3$ .