Schottky defect is observed in crystals when ……………. .

Options

A. some cations move from their lattice site to intentitial sites
B. equal number of cations and anions are missing from the lattice
C. some lattice sites are occupied by electrons
D. some impurity is present in the lattice.

Answer

B

Explanation

Schottky defect is observed in crystal when equal number of cations and anions aremissing from the lattice. Thus, density of solid. Decrease

When some cations move from their lattice site to intersitial site is known as Frenkel defect. When some impurity is present on crystal is known as impiarity defect.
When lattice iste is occupied by electron, this type of defect is known as metal excess defect. Hence except (b) all statments are incorrect regarding Schottky Schottky defect.