In an ideal crystal, the entropy of the constituents at absolute zero temperature (0K) is zero. However, the crystals generally suffer from certain defects also called imperfections They may be both electronic and atomic in nature. The atomic imperfections may be stoichiometric (Schottky and Frenkel defects) or non-stoichiometric (metal excees and metal deficiency defects). In addition to these, there are impurity defects which are caused by the addition of certain impurities of metals and this is known as dopping. The dopping leads to semi conductors which may be either n-type or p-type in nature.
Ionic solids with Schottky defects contain in their structure
A. Equal number of cation and anion vacancies
B. Anion vacancies and interstitial anions
C. Cation vacancies
D. Cation vacancies and interstitial cations
