Question

The spin magnetic moment of cobalt in $Hg\left[Co\right(SCN{)}_4]$ is

• A. $\sqrt{3}$
• B. $\sqrt{8}$
• C. $\sqrt{15}$
• D. $\sqrt{24}$

Answer 1

The correct option is C $\sqrt{15}$

The spin only magnetic moment is given by the formula ${\mu }_{eff}=\sqrt{n(n+2)}B.M.$.

The cobalt atom in $Hg\left[Co\right(SCN{)}_4]$ carries +2 charge and has $3d^7$ as the outer electronic configuration.

Here Hg shows +2 oxidation state and the compound is known as Mercuric tetrathiocyanatocobaltate(II).

It contains three unpaired electrons.

For three unpaired electrons, the expression becomes ${\mu }_{eff}=\sqrt{3(3+2)}B.M.=\sqrt{15}B.M.$

Therefore, option C is correct.