Question

The magnetic moment of ${\left[Mn(CN{)}_6\right]}^{3-}$ is $2.8BM$ and that of ${\left[MnB{r}_4\right]}^{2-}$ is $5.9BM$ The hybridization and geometries of these complex ions

• A. $s{p}^3{d}^2$ octahedral and dsp ${}^2$ tetrahedral
• B. $d^{2}s{p}^3$ octahedral and $ds{p}^2$ square plannar
• C. $d^{2}s{p}^3$ octahedral and $s{p}^3$ tetrahedral
• D. $s{p}^3{d}^2$ octahedral and $s{p}^3$ square plannar

Answer 1

Answer: (C)

${\left[Mn(CN{)}_6\right]}^{3-}:M{n}^{3+}=3d^{4}4s^{\circ }=t_{2g}^{2,1,1}e{g}^{\circ \circ }=d^{2}s{p}^3$ hybridised
no. of unpaired electrons $=2$
magnetic moment $={\mu }_B=\sqrt{2\times 4}BM\simeq 2.8BM$
${\left[MnB{r}_4\right]}^{2-}:M{n}^{2+}=3d^{5}4s^{\circ }=e{g}^{1,1}{t}_{2g}^{1,1,1}=s{p}^3$ hybridised
no. of unpaired electrons $=5$
magnetic moment $={\mu }_B=\sqrt{5\times 7}BM\simeq 5.9BM$