Question

Schottky defect is observed in which one of the following?

• A. $Ca{F}_2$
• B. $ZnS$
• C. $AgCl$
• D. $CsCl$

Answer 1

The correct option is D $CsCl$

Schottky defect is a kind of point defect in a crystal lattice. It happens to occur when oppositely charged ions leave their lattice sites creating vacancies. The vacancies formed are in such a way that the overall neutrality is maintained is ionic solid. The surrounding atoms then move to fill these vacancies causing new vacancies to form. These defects tend to decrease the density of the crystal. Normally, these defects are typical is highly ionic compounds, highly coordinated compounds and where there is only small difference in size of cations and anions of the crystal lattice.

Example: $NaCl,KCl,CsCl,AgBr,KBr,Ce{O}_2,cubicZn{O}_2,U{O}_2,Th{O}_2,Pu{O}_2$