Define the following term
Schottky defect
Explain the following terms with suitable examples
Schottky defect
What are Schottky defect
Solution 1
Schottky defect is defined as the one in which equal number of cations and anions are missing from their lattice positions in an ionic compound.
Solution 2
Schottky defect: Schottky defect is basically a vacancy defect shown by ionic solids. In this defect, an equal number of cations and anions are missing to maintain electrical neutrality. It decreases the density of a substance. Significant number of Schottky defects is present in ionic solids. For example, in NaCl, there are approximately 106 Schottky pairs per cm3 at room temperature. Ionic substances containing similar-sized cations and anions show this type of defect. For example: NaCl, KCl, CsCl, AgBr, etc.
Solution 3
Schottky defect:
1) Sometimes during crystallisation, some of the places of the constituent particles
remain unoccupied and the defect generated is called vacancy defect or Schottky defect
2) The unoccupied positions are called vacancies
3) It results in the decrease in density of the substance.
4) In case of ionic solids, cations and anions in stoichiometric proportions remain absent from their position to maintain electrical neutrality.
5) In Ionic compounds, this defect is known as Schottky defect
6) The defects are observed in solids with cations and anions having almost equal size like NaCl, KCl, CsCl, etc.
