Question

Which of the following statements are correct in context of point defects in a crystal ?

• A. AgCl has anion Frenkel defect and CaF2 has Schottky defects
• B. AgCl has cationFrenkel defects and CaF2 has anion Frenkel defects
• C. AgCl as well as CaF2have anion Frenkel defects
• D. AgCl as well as CaF2 has Schottky defects

Answer 1

Answer: (B)

AgCl has cationFrenkel defects and CaF2 has anion Frenkel defects

Answer 2

Since Ag+ (cation) is smaller than Cl– (anion) & hence cation is present in voids.

In CaF2 , $F_{anion}^{-}$ is smaller.