Chemistry - Solid State Question with Solution | TestHub

In ccp,${\mathrm{O}}^{2-}$ions are 4.
Hence total negative charge = -8
Let$\mathrm{A}{\mathrm{l}}^{3+}$ions be x, and$\mathrm{M}{\mathrm{g}}^{2+}$ions be y.
Total positive charge = 3x + 2y
$\Rightarrow 3\mathrm{x}+2\mathrm{y}=8$
This relation is satisfied only by x = 2 and y = 1.
Hence number of$\mathrm{A}{\mathrm{l}}^{3+}=2$
and number of$\mathrm{M}{\mathrm{g}}^{2+}=1$
$\Rightarrow$n = fraction of octahedral holes occupied by$\mathrm{A}{\mathrm{l}}^{3+}$
$=\frac{2}{4}=\frac{1}{2}$
and m = fraction of tetrahedral holes occupied by$\mathrm{M}{\mathrm{g}}^{2+}$
$=\frac{1}{8}$