Question

10. Differentiate schottky and Frenkel defect.

Answer 1

hey mate
here is ur ans

schottky defect
* size of cation and anion should be comparable
* when anio. leave it's lattice site so then cation also leave it lattice site to maintain the electrical neutrality so that create a vacancy
* for ex Nacl,
Frackel defect
* anion bigger than the cation size
* cation leave this lattice site and occupied the interstitial sites
* no effect on density also
* for ex Zns
hope it help yu

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.