Silver bromide (AgBr) is a compound that exhibits two types of point defects: Frenkel and Schottky defects. Understanding these defects helps in explaining the behavior of ionic solids.
1. Frenkel Defect: This defect occurs when an ion moves from its lattice site to an interstitial site, creating a vacancy at its original site while occupying an interstitial position. In AgBr, this typically involves silver ions (Ag+) due to their small size that enables them to hop into the interstitial spaces.
2. Schottky Defect: This defect happens when equal numbers of cations and anions are missing from the lattice, maintaining electrical neutrality. Both Ag+ and Br- ions are absent from their lattice sites, essentially reducing the density of the crystal.
AgBr is unique in that it simultaneously exhibits both Frenkel and Schottky defects due to the size suitability of Ag+ ions for Frenkel defects and the general property of ionic compounds with high density to exhibit Schottky defects.
Therefore, the correct observation in AgBr is "Both Frenkel and Schottky defects."