Question

Which one of the following crystals does not exhibit Frenkel defefect

• A. AgBr
• B. AgCl
• C. KBr
• D. ZnS

Answer 1

The correct option is C

KBr

$\Rightarrow$ Frenkel Defect $\to$ If an ion is missing from lattice site and occupying interstitial site .
$\Rightarrow$ Favoured in compounds: with low coordination no.
$\Rightarrow$ Favoured in compounds in which there is large difference in size of cations and anions.
$\ast$ Look for the crystal where cation and anion are of similar size.

$\to A{g}^{+}$ and $Z{n}^{2^{+}}$ are very small.
$\Rightarrow$ KBr is the answer.