Frenckel Defect consequence..!

What are the conditions and consequence of Frenkel defect..

Ans. Conditions for the formation of Frenkel defect

(i) Frenkel defect occurs in ionic compounds with large difference between sizes of cation and anion.

(ii) The ions of ionic compounds must be having low coordination number.

(ii) The crystal as a whole remains electrically neutral because the equal numbers of cation and anions are present.

(a) Write examples of ionic solids with Frenkel defect.

Ans. ZnS, AgCl, AgBr, AgI, CaF, etc

(b) Name the type of point defect that occurs in a crystal of zinc sulphide?

(c) Why Frenkel defect is found in AgCI? 

Ans. Frenkel defect is found in AgCl due to small size of silver cation (Ag+)

(d) Why is Frenkel defect is not found in pure alkali

Ans. Frenkel defect is not found in pure alkali metal halide due to large size of alkali metal ions which cannot fit into interstitial sites.

(e) Name the ionic compound which shows both Schottky and Frenkel defect?

Ans. Silver bromide (AgBr)