Question

The spin-only magnetic moment of ${\left[cr{F}_6\right]}^{4-}$ (atomic number of Cr is 24) is

• A. 0
• B. 1.73 BM
• C. 2.83 BM
• D. 4.9 BM

Answer 1

Answer: (D)

${}_{24}Cr=\left[Ar\right]3d^{5}4s^1,C{r}^{2+}$
F- is a weak field ligand, ${△}_0<P,Nopairing$
${\left[Cr{F}_6\right]}^{-4}=$
No. of unpaired $\overline{e}$ =4, Spin only magnetic moment $\left(\mu \right)$
$=\sqrt{n\left(n+2\right)}=\sqrt{4\times 6}=\sqrt{24}=4.9BM$