What is meant by Schottky defect?
A Schottky defect is an excitation of the site occupations in a crystal lattice leading to point defects named after Walter H. 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 is Schottky defect explain with example?
(i) Schottky defect. Some atoms or ions are missing from their normal lattice sites. Unoccupied lattice sites are called vacancies or holes. For example, in the crystal lattice of NaCl, equal number of cations and anions are missing to maintain electrical neutrality. (ii) Frenkel defect.
Which compound shows both Schottky and Frenkel defect?
AgBr shows both Frenkel and Schottky defects because the radius ratio for AgBr is intermediate.
What type of stoichiometric defect is shown by?
→ Schottky Defect: This defect occurs when oppositely charged ions leave their lattice site creating vacancies in such a way that electrical neutrality of crystal is maintained. It is generally seen in highly ionic compounds where difference in size of cation and anion is small. Was this answer helpful?
What is the other name of of dislocation defect?
In materials science, a dislocation or Taylor’s dislocation is a linear crystallographic defect or irregularity within a crystal structure that contains an abrupt change in the arrangement of atoms. The movement of dislocations allow atoms to slide over each other at low stress levels and is known as glide or slip.
Which of the following defect decreases the density?
Vacancy and Schottky defect which lead to decrease the density both are the types of a stoichiometric defect. In case of Frenkel defect and interstitial defect, there is no change in density of substance.
Which defect causes decrease in the density of crystal?
Schottky defect
Which one of the following has Frenkel defect?
AgBr has Frenkel defects due to large difference in the size of Ag⊕ and Brɵ ions.
Which of the following is non stoichiometric defect?
Non-Stoichiometric Defects Nonstoichiometric inorganic solids contain the constituent elements in a non-stoichiometric ratio due to defects in their crystal structures. These defects are of two types: (i) metal excess defect and (ii) metal deficiency defect.
Which one of the following crystals does not show Frenkel defect?
Since in NaCl, KCl the size of anions and cations are similar, they do not show Frenkel defects. > In CsCl and AgCl, there is a large difference in the size of anions and cations , but CsCl being an alkali halide does not show Frenkel defect.
Which is not Frenkel defect?
Solution : In pure alkali halides, Frenkel defects are not found since the big alkali metal ions cannot get into the interstital sites, Frenkel defects are found in silver halides beacause of the small size of the Ag+ ion.
Which is not correct for Frenkel defect?
Which of the following statement for crystals having Frenkel defect is not correct? (D) Pure Alkali halides do not have Frenkel defect.
In which of the following defect some of the cations are arranged in the interstitial site?
Frenkel defect
What is defect or imperfection?
Any deviation from the perfectly ordered arrangement constitutes a defect or imperfection. These defects sometimes called thermodynamic defects because the number of these defects depend on the temperature. The electrons and holes in solids gives rise to electronic imperfections. …
Which type of defect has the presence of cations?
What is metal deficiency defect?
In metal deficiency defect, a cation is missing from its lattice site. To maintain electrical neutrality, one of the nearest metal ions acquires an extra positive charge. This type of defect occurs in compounds where the metal can exhibit variable valency. e.g., Transition metal compounds.