Question

why schottky defect is found in those compounds having high coordination number and small difference in size of cations and anions and why reverse is true in frenkel defect

Answer 1

because frenkle defect also shows the interstitial defect which can possible only when the size of cation and anion acquire a large difference but schottky defect shows vacany defect only in proper manner in which similar sizes cations and anions are leave their sites to maintain electrical neutrality...