What is the other name of Schottky defect?
What is the other name of Schottky defect?
Schottky. In elemental crystals it refers to simple lattice vacancies, also called valency defects. In ionic crystals, this defect forms when oppositely charged ions leave their lattice sites and become incorporated for instance at the surface, creating oppositely charged vacancies.
What are the differences between Frenkel and Schottky defects?
In Schottky defect the difference in size between cation and anion is small. Frenkel defect contains ionic crystals where the anion is larger than the cation. Both anion and cation leave the solid crystal. Usually the smaller ion cation leaves its original lattice structure.
What is the other name of Frenkel defect?
dislocation defect
Difference between Schottky and Frenkel Defect
| Schottky Defect | Frenkel Defect |
|---|---|
| Compounds such as KCl, KBr, CsCl etc. show Schottky defect. | Compounds such as NaCl, ZnS, AgI etc. show Frenkel defect. |
| It is also known as valency defect. | It also known as dislocation defect. |
What is difference between interstitial defect and Frenkel defect?
In Interstitial defect, atom occupies the interstitial space of the lattice structure of solid crystal. In Substitutional defect, the foreign atom occupies only the lattice site of a crystalline solid.
How are Schottky defects calculated?
The number of Schottky defects (n) present in an ionic compound containing N ions at temperature Tis given by n = Ne E/2KT, where E is the energy required to create ‘n’ Schottky defects and K is the Boltzmann constant. If the mole fraction of Schottky defect in NaCl crystal at 2900 K is X. then calculate -In(x).
What are Schottky and Frenkel defects give examples?
1) Schottky defect: The ionic compounds such as NaCl, KCl, KBr, AgBr and CsCl show this defect. 2) Frenkel defects: This defect is found in silver halides such as AgCl, AgBr and AgI because of the small size of the Ag+ ion.
Why AgBr shows both Frenkel and Schottky defect?
Schottky defect arise due to missing of ions from their lattice point and Frenkel defect arise when the missing ions occupy interstitial sites. The radius of AgBr is intermediate hence it shows both Frenkel and Schottky defects. The major defect in AgBr is Frenkel defect.
Does KCl show Frenkel defect?
Since in NaCl, KCl the size of anions and cations are similar, they do not show Frenkel defects.
What is Frenkel disorder?
The Frenkel defect (also known as the Frenkel pair/disorder) is a defect in the lattice crystal where an atom or ion occupies a normally vacant site other than its own. As a result the atom or ion leaves its own lattice site vacant.
What is Frenkel defect explain it?
A Frenkel defect is a type of point defect in crystalline solids, named after its discoverer Yakov Frenkel. The defect forms when an atom or smaller ion (usually cation) leaves its place in the lattice, creating a vacancy and becomes an interstitial by lodging in a nearby location.
What are the types of stoichiometric defects?
Types of stoichiometric defects:
- Vacancy Defects.
- Interstitial defects.
- Frenkel Defects.
- Schottky Defects.
What is meant by Schottky defect?
: a defect in a crystal lattice created by removing an ion from its normal site and placing it on the crystal surface.
When does a Frenkel defect occur in a Schottky Crystal?
Frenkel defect usually occurs in those ionic crystals where size of anion is quite large as compared to that of the cation. In Schottky defect, both cation and anion leave the solid crystal.
How did the Schottky defect get its name?
Schottky defect is a form of point defect that forms due to the loss of an atom in stoichiometric units of the crystal lattice. This point defect got its name after the scientist Walter H. Schottky.
How does the Schottky defect affect the density?
Schottky defect leads to changes ibn the density of the crystal because the volume remains the same while the mass is reduced because ions or atoms have left the crystal and created the vacancies Frenkel defect has no effect in the density because the ions or atoms are just being displaced. So the mass remains the same and the density is unchanged.
Where does the Frenkel defect occur in a lattice?
Then both the mass and volume of the lattice remain unchanged. The Frenkel defect is found mostly in ionic compounds. Unlike Schottky defect, the Frenkel defect is found in lattices composed of atoms or ions that have considerable differences between their sizes. One or more atoms or ions may undergo Frenkel defect.
