Understanding Frenkel Defects

The video tutorial explains the Frenkel defect in ionic crystals, where a cation leaves its lattice site and occupies an interstitial site, creating a vacancy and an interstitial defect. This defect, also known as a dislocation defect, is common in ionic compounds with low coordination numbers. The tutorial highlights that the number of cations and anions remains unchanged, and the density of the crystal is unaffected. The defect increases the dielectric constant of the crystal.

What is created when a cation leaves its lattice site in a Frenkel defect?

• A vacancy and an interstitial defect

• An anion

• A covalent bond

• A new crystal

Which type of ionic compounds are more likely to exhibit Frenkel defects?

• Compounds with high coordination numbers

• Compounds with small ionic differences

• Compounds with low coordination numbers

• Compounds with equal numbers of cations and anions

Which of the following is an example of a compound that shows Frenkel defect?

• Sodium chloride

• Zinc sulphide

• Magnesium oxide

• Calcium carbonate

What remains unchanged in an ionic crystal before and after a Frenkel defect?

• The color of the crystal

• The number of cations and anions

• The shape of the crystal

• The temperature of the crystal

How does a Frenkel defect affect the dielectric constant of a crystal?

• It decreases the dielectric constant

• It has no effect on the dielectric constant

• It increases the dielectric constant

• It makes the dielectric constant zero