Question

What type of crystal defect is indicated in the diagram below ? ${ Na^{+} Cl^{-} Na^{+} Cl^{-} Na^{+} Cl^{-}}$ ${Cl^{-} \Box \, Cl^{-} Na^{+} \Box Na^{+}}$ ${Na^{+} Cl^{-} \Box Cl^{-} Na^{+} Cl^{-}}$ ${Cl^{-} Na^{+} Cl^{-} Na^{+} \Box Na^{+}}$

• A. Interstitial defect
• B. Schottky defect
• C. Frenkel defect
• D. Frenkel & Schottky defects

Answer 1

Answer: (B)

Schottky defect

Answer 2

Schottky defect is a defect which is produced when one cation and anion are missing from their respective positions leaving behind a pair of holes. The crystal as a whole remains neutral because the number of missing positive ions (cations) and negative ions (anions) is the same.