Question

Density of a crystal decreases due to Schottky defect and remains constant due to Frankel defect.
If true enter 1,else enter 0.

Answer 1

A Schottky defect is a type of point defect in a crystal lattice. In ionic crystals, the defect forms when oppositely charged ions leave their lattice sites, creating vacancies. These vacancies are formed in stoichiometric units, to maintain an overall neutral charge in the ionic solid. The vacancies are then free to move about as their own entities. Normally these defects will lead to a decrease in the density of the crystal.

The Frenkel defect consists in the displacement of an atom from its lattice position to an interstitial site, creating a vacancy at the original site and an interstitial defect at the new location.This defect does not have any impact on the density of the solid as it involves only the migration of the ions within the crystal, thus preserving both the volume as well as mass.