Question

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

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

Answer 1

Answer: (B)

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.