Question

Alkali halides do not show Frenkel defect because:

• A. cation and anions have almost equal size
• B. there is a large difference in size of cation and anions
• C. cation and anions have low coordination number
• D. anions cannot be accommodated in voids.

Answer 1

Answer: (A)

cation and anions have almost equal size

Frenkel defect is possible in the compounds in which the size of cations and anions are different. In this defect, the smaller ion comes to interstitial place.

In Alkali halides the size of cations and anions is almost equal. So the ion size is large and they cannot get into the interstitial site.

So, these kinds of compounds do not show Frenkel defect.

Hence, Option "A" is the correct answer.