question_answer

  Explain the following terms with suitable examples. (a) Schottky defect                                                                                                                                                                         1 (b) Interstitial defect.                                                                                                                                                                     1

Answer:

                                                                (a) Schottky defect: This type of defect is created when one positive ion and one negative hp ion are missing                 from their respective positions learning behind a pair of holes.                                                                                  1 These are more common in ionic compounds with high co-ordination number, e.g.,                                                                                                                                                                                            (b) Frankel defect: This defect is created when an ion leaves its correct lattice and occupies an interstitial site. There is no change in the density of crystal, e.g., .                                                                                                               1