Explain Schottky and Frenkel defects.

Which of the following statements are not true regarding Schottky and Frenkel defects-

State the difference between Schottky and Frenkel defects. Which of these two changes the density of the solid ?

Mention two differences between Schottky and Frenkel defects.

Name a crystalline solid which is likely to develop both Schottky and Frenkel defects.

Explain Schottky defect in Stoichiometric crystals. What are the consequences of Schottky and Frenkel defects in crystals ?

In what way, do Schottky and Frenkel defects differ from each other ?

What is stoichiometric defect? What kind of defects are Schottky and Frenkel defects? Which one of these two defects is associated with decrease in density of the crystal, and which one is associated with no change in density? Give reasons.

(a) A crystalline compound formed by element A and B has face-centred cubic unit cell. The corners and the face centres are occupied by A and B atoms respectively. If one of the corner atoms is found missing then what would be the formula of the compound? (b) Give an example of a compound which exhibits both Schottky and Frenkel defects.

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. In stoichiometric defects, the ratio of positive and negative ions as indicated by chemical formula of the compound:

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. Which of the following is correct ?