Question

Schottky defect in a crystal is observed when :

• A. unequal number of cations and anions are missing from the lattice
• B. equal number of cations and anions are missing from the lattice
• C. an ion leaves its normal site and occupies an interstitial site
• D. no ion is missing from its lattice site

Answer 1

Answer: (B)

equal number of cations and anions are missing from the lattice

Schottky defect arise when equal number of cations and anions are missing from the lattice. It is a common defect in ionic compounds of high coordination number* where both cations and anions are of the same size. Due to this density of crystal decreases and begins to conduct electricity to a smaller extent. Examples: KBr,NaCl,KCl.