Question

{"given":"We need to identify which ionic compounds exhibit Schottky defects among NaCl, CsCl, and AgBr. Schottky defect is a type of point defect in ionic crystals.","key_observation":"Schottky defect occurs in ionic crystals when equal numbers of cations and anions are missing from their lattice positions, creating vacancies while maintaining electrical neutrality. This defect is favored when the size difference between cation and anion is small, and it commonly occurs in compounds with high coordination numbers.","option_analysis":[{"label":"(A)","text":"NaCl","verdict":"correct","explanation":"NaCl is the classic example of Schottky defect. In rock salt structure, both Na⁺ and Cl⁻ ions can leave their lattice positions simultaneously, creating paired vacancies that maintain charge neutrality."},{"label":"(B)","text":"CsCl","verdict":"correct","explanation":"CsCl also exhibits Schottky defect. In the cesium chloride structure, Cs⁺ and Cl⁻ ions can create paired vacancies, maintaining electrical neutrality of the crystal."},{"label":"(C)","text":"AgBr","verdict":"correct","explanation":"AgBr shows Schottky defect where Ag⁺ and Br⁻ ions leave their lattice positions together. This creates paired vacancies while preserving the overall charge balance in the crystal."},{"label":"(D)","text":"All of these","verdict":"correct","explanation":"Since NaCl, CsCl, and AgBr all exhibit Schottky defects, this option correctly encompasses all the individual correct answers, making it the most comprehensive and accurate choice."}],"answer":"(D)"}