Explain the following term with a suitable example:
$(i)$ Schottky defect

(N/A) $(i)$ Schottky defect: Schottky defect is a type of vacancy defect shown by ionic solids.
In this defect,an equal number of cations and anions are missing from their lattice sites to maintain electrical neutrality.
It decreases the density of the substance.
$A$ significant number of Schottky defects are present in ionic solids.
For example,in $NaCl$,there are approximately $10^{6}$ Schottky pairs per $cm^{3}$ at room temperature.
Ionic substances containing cations and anions of similar sizes show this type of defect.
Examples include $NaCl$,$KCl$,$CsCl$,and $AgBr$.