What are stoichiometric defects in ionic solids?
Stoichiometric defects are intrinsic defects in which the ratio of cations to anions remains exactly the same as represented by the molecular formula. They are mainly of two types: Vacancy defects in which an atom is not present at its lattice sites causing that lattice site to be vacant and create a vacancy defect.
What are the stoichiometric defects found in ionic crystals?
the stoichiometric defects in the ionic crystal are the defects in which the equal no. of cations and anions from the crystal lattice are removed but the ratio of the cations and anions remains the same as the preceding ratio…..these defects results in the maintenance of electrical neutrality of crystal ….
What type of stoichiometric defect is shown by HCL?
The silver ions are much smaller than the chloride ions. So, the silver ions occupy the interstitial sites, leaving a corresponding number of normal lattice sites vacant. Hence, the correct answer is Frenkel defect.
What are the four types of stoichiometric defects?
Stoichiometric Defect: In this kind of point defect, the ratio of positive and negative ions (Stoichiometric) and electrical neutrality of a solid is not disturbed.
What is difference between Schottky and Frenkel defect?
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 are the types of stoichiometric defects?
-There are two types of stoichiometric defects. One is schottky defect and the other is frenkel. Schottky defect occurs when equal numbers of cations and anions are missing from the lattice. -Frenkel defect arises when an ion is missing from its actual lattice site and it occupies any interstitial site.
What is difference between Schottky defect and Frenkel defect?
What is Schottky defect give an example?
Examples. This type of defect is typically observed in highly ionic compounds, highly coordinated compounds, and where there is only a small difference in sizes of cations and anions of which the compound lattice is composed. Typical salts where Schottky disorder is observed are NaCl, KCl, KBr, CsCl and AgBr.
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.
What are two types of stoichiometric defect?
-There are two types of stoichiometric defects. One is schottky defect and the other is frenkel. Schottky defect occurs when equal numbers of cations and anions are missing from the lattice.
What are the two types of 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.
What is Schottky defect example?
What kind of defects do not disturb the stoichiometry?
The defects do not disturb the stoichiometry (the ratio of numbers of positive and negative ions) are called stoichiometric defects. These are of following types, (a) Interstitial defect: This type of defect is caused due to the presence of ions in the normally vacant interstitial sites in the crystals.
When do Schottky defects occur in ionic compounds?
(b) Schottky defect: This type of defect when equal number of cations and anions are missing from their lattice sites so that the electrical neutrality is maintained. This type of defect occurs in highly ionic compounds which have high co-ordination number and cations and anions of similar sizes. e.g., NaCl, KCl, CsCl and KBr etc.
Why are ionic solids brittle to the touch?
They are brittle because of low mobility of defects called dislocations present in ionic solids. We all know that metals are ductile and they deform plastically. This is because of the movement of dislocations on certain crystallographic planes of metals.
When does a Frenkel defect occur in ionic solids?
Frenkel Defect: In ionic solids generally, the smaller ion (cation) moves out of its place and occupies an intermolecular space. In this case, a vacancy defect is created on its original position and the interstitial defect is experienced at its new position.
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