The defect that occurs due to a displacement of an ion is known as……………a.Schottky defectb.Impurity defectc.Vacancy defectd.Frankel defect

The defect that occurs due to a displacement of an ion is known as d. Frankel defect.

Explanation:

1. Schottky defect refers to the vacancy created when an atom or ion leaves its lattice site, resulting in the absence of both cation and anion in a crystal, which maintains the overall charge balance.
2. Impurity defect occurs when foreign atoms or ions are introduced into the crystal lattice, leading to a change in the composition.
3. Vacancy defect is specifically related to the absence of an atom or ion in the lattice where one would normally expect to find it.
4. Frankel defect, on the other hand, specifically involves the displacement of an ion from its normal lattice position, creating a vacancy and an interstitial site.

In summary, the correct answer is Frankel defect because it directly corresponds to the displacement of ions in the lattice.