Statement I: Frenkel defects are vacancy as well as interstitial defects. Statement II: Frenkel defe

Question

Statement I: Frenkel defects are vacancy as well as interstitial defects. Statement II: Frenkel defect leads to colour in ionic solids due to presence of F-centres.

Professor PC Thomas Classes · Answer

Statement I is true (an ion leaves its site creating a vacancy and occupies an interstitial site). Statement II is false because F-centers (which impart color) are formed due to metal excess defects (anion vacancies filled with electrons), not Frenkel defects.