Question

Which of the following point defects are shown by AgBr(s) crystals ?

1. Schottky defect

2. Frenkel defect

3. Metal excess defect

4. Metal deficiency defect

(a) 1 and 2 (b) 3 and 4 (c) 1 and 3 (d) 2 and 4

Answer 1

Answer: (a) 1 and 2

AgBr shows both Schottky, as well as the Frenkel detect. In AgBr, both $A{g}^{+}$ and $B{r}^{-}$ ions are absent from the lattice causing the Schottky defect. However, $A{g}^{+}$ ions are mobile so they have a tendency to move aside the lattice and trapped in interstitial site hence, cause, Frenkel defect.