Question

difference between schottky and frenkel defect

Answer 1

SCHOTTKY DEFECT ------

1)schottky defect means when equal number of cations and anions are missing from the letters points of the solid

2)this defect is shown by celebs having high co-ordination number and small difference in size of cation and anion

3)in schottky defect the density of the solid decreases
***examples NaCl, KCl etc***

FRENKEL DEFECT -----

1)frenkel defect is a defect when a cation is missing from its lattice point and occupy interstitial position

2)this defect is shown by solids having low co-ordination number and large difference in size of cation and anion

3)here density of the solid remains same because no ions escape

Answer 2

Answer:

Frenkel Defect:

• Ionic solids containing large differences in the sizes of ions show this type of defect.
• When the smaller ion (usually cation) is dislocated from its normal site to an interstitial site, Frenkel defect is created.
• It creates a vacancy defect as well as an interstitial defect.
• Frenkel defect is also known as dislocation defect.
• Ionic solids such as AgCl, AgBr, AgI, and ZnS show this type of defect.  

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 similarsized cations and anions show this type of defect.
• For example: NaCl, KCl, CsCl, AgBr, etc.