Frenkel defect, first discovered by and named by Yakov Frenkel is a type of point defect found in crystalline solids.
This defect forms when a smaller atom or ion, generally cation, leaves its usual lattice position and occupies an interstitial position instead.
By leaving its position, it creates a vacancy at its lattice point.
Since Frenkel defect only involves the migration of ions within the lattice, the density and volume remains unchanged (mostly).
This defect is usually found in those ionic crystals in which there is a large size difference between the anion and the cation.
Some examples of solids showing Frenkel defect are zinc sulfide, silver chloride, etc.
Final Answer:
Frenkel defect is a point defect found in crystalline solids due to migration of smaller ion from its position to interstitial position. Since Frenkel defect only involves the migration of ions within the lattice, the density remains unchanged.
