The cobalt atom in \(Hg \left[ Co ( SCN )_{4}\right]\) carries +2 charge and has \(3 d ^{7}\) 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 \(\mu_{e f f}=\sqrt{3(3+2)} B \cdot M .=\sqrt{15} B \cdot M\)
Therefore, option \(C\) is correct.
$\left[ Ru \left( H _{2} O \right)_{6}\right]^{2+}$ની ચુંબકીય ચાકમાત્રા ($BM$ માં) શું હશે?