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wats the diff btwn frenkel and schottky defects?

Frankel defect arrises whe n some of the ions of the lattive occupy intertstitial sites leaving lattice sites vacant . This defect is generally found in ionic crystals where anion is much more larget than the cation .e.g., AgBr , ZnS , etc.  Due to this defect density does not change , electrical conductivity increases to a small extent & ther is not change in the overall chemical composition of the crystals.

Whereas , Schottky defect arises when equal no. of cation & anions are missing from the lattice sites . It is a common defect in ionic compounds of high coordination no. where both cations & anions are off the same size , e.g., KCl, NaCl, KBr, etc.  Due to this defect density decreases & it becomes to conduct electricity to a smaller extent.

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 frenkels defects is showns by the ionic compounds having large difference in their size of ions

this defect is created when smaller ion delocalised from its normal position to an interstitial site

schottky defect this defect is shown by the ionic compounds in which equal number of anions and cations are missing to maintain electical neutralitiy

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schotty defect
1. high coordination no.,

2. ions of almost similar sizes,

3. eg. NaCl,AgBr

frenkel defect
1. low coordination no.,

2. anions are much larger in size than the cation,

3. eg. ZnS,AgBr

hope u understood.

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Frenkel defect

1. Both vacancy defect & interstitial defects are created

2.Do not make any change in the dencity of the crystal

3.Anions are larger than cations

4. Delocalisation of ions takes place

eg: AgI,AgCl,ZnS

Schottky defect

1. Only vacancy defect is created

2. Decreases the dencity of the crystal

3. Both ions aare of similar size

4. Missing of ions takes place

eg: NaCl,KCl,CsCl

AgBr shows both this defects

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