CBSE Class 12-science Answered
Schottky and Frenkel defects. Schottky defects is a vacancy defect, it decreases the density and equal numbers of cations and anions are missing from the lattice. This effect is shown by ionic substances where there is less difference in ionic size e.g.NaCl, KCl, CsCl. A Frenkel defect is form of interstitial defect when an atom or ion leaves its place in the lattice (leaving a vacancy), and lodges nearby in the crystal (becoming an interstitial). The number of interstitials formed will equal the number of vacancies formed and the density remains the same. This effect is shown by ionic substances where there is a large difference in ionic size e.g. ZnS, AgCl, AgBr, AgI.