Question

A solid made up of ions of A and B possessing edge length of unit cell $0.564$ nm has four formula units. Among the two ions, the smaller one occupies the interstitial void and the larger ion occupies the space lattice with ccp type of arrangement. One molecule of solid has mass $9.712\times {10}^{-23}$ g. Which defect is solid AB supposed to show?

• A. Schottky defect
• B. Frenkel defect
• C. Non-stoichiometric defect
• D. None of the above

Answer 1

The correct option is A Schottky defect

The solid AB is supposed to show Schottky defect.
Schottky defect arises due to a vacancy at an anion site, which of course is accompanied by a vacancy at a cationic site to maintain the electrical neutrality of the system.
Schottky defect occurs in ionic compounds with high coordination number and where the cation and anion have similar sizes.