Question

AgCl show frenkel defect whle NaCl crystal does not. why?

Answer 1

Dear student!

The Frenkel defect is that in which one smaller ion (usually cations) move from its lattice position to an interestitial site i.e. a tetrahedral /octahedral hole to form a vacancy in the lattice.

Of course, AgCl has the defect because, the radius of AgCl is intermediate and since, the size of Ag⁺ cation is smaller than chloride ion so it can move to interstitial spaces causing Frenkel defect while in NaCl (alkali metal halide) they have larger size of cations which do not fit into voids and so the effect is not shown by the halides.