Question

Select the incorrect statement for schottky defect.

• A. Vacant cation and anion sites in ratio 1:1 in an $MX$ lattice
• B. Vacant cation and anion sites in ratio 1:2 in an $M{X}_2$ lattice
• C. Vacant cation and anion sites in ratio 2:1 in an $M_{2}X$ lattice
• D. In each unit cell either cation or anion must be missing

Answer 1

The correct option is D In each unit cell either cation or anion must be missing

$\begin{array}{c}\text{While in option D, It is not neeassary that cation or anion from}\\ \text{every unit cell become vacant.}\end{array}$

$\begin{array}{c}\text{In schottky defect, the molecule should remain}\\ \text{neutral. So, positive and negative charge becoming}\\ \text{vacant must be equal.}\end{array}$