Question

In which of the following crystals are the alternate tetrahedral voids occupied?

• A. $NaCl$
• B. $ZnS$
• C. $Ca{F}_2$
• D. $N{a}_{2}O$

Answer 1

The correct option is B $ZnS$

$ZnS$ crystallizes forms a cubic close-packed array where $S^{2-}$ ions with $Z{n}^{2+}$ ions occupies tetrahedral holes.
If $S^{2-}$ ions occupy the lattice points of a face-centered cubic unit cell and $Z{n}^{2+}$ ions are packed into every other tetrahedral hole, we get the unit cell of $ZnS$.