Question

why does AgBr show both frenkel and schottky defect

Answer 1

Schottky defect arise due to missing of ions from their lattice point and Frenkel defect arise when the missing ions occupy interstitial sites. Schottky defect is observed in crystals having high coordination No. Frenkel defect is observed in those crystals where there is large difference in size of cation and anion. In AgBr , Ag⁺ is small in size while Br^- is large in size, which accounts for large differences in the size of anions and cation, thus show Frenkel defect while AgBr is an ionic compound with high coordination no. that is why it shows schottky defect also.