(આપેલ : $Cr$ નો પરમાણુક્રમાંક $24$ છે.)
$\mathrm{Cr}_2 \mathrm{O}_3$ Amphoteric oxide
In $\mathrm{CrO}, \mathrm{Cr}$ exist as $\mathrm{Cr}^{+2}$ and have $\mu$ only $=4.90$
In $\mathrm{Cr}_2 \mathrm{O}_3, \mathrm{Cr}$ exist as $\mathrm{Cr}^{+3}$ and have $\mu$ only $=3.87$
Sum of spin only magnetic moment
$=4.90+3.87=8.77$
$\mu_{\text {only }}=877 \times 10^{-2}$
Ans. $877$
............ $BM$ છે (નજીકનો પૂણાંક)
(આપેલ : પરમાણુ ક્માંક $\mathrm{V}=23, \mathrm{Mn}=25, \mathrm{Cr}=24$ )