Question

Which of the following is not a defect?

a) Frenkel Defect

b) Interstitial Atom

c) Substitutional Atom

d) Dislocation

Answer 1

a) Frenkel Defect : which is a type of defect in crystalline solids wherein an atom is displaced from its lattice position to an interstitial site, creating a vacancy at the original site.

b) Interstitials defects are a variety of crystallographic defects where atoms assume a normally unoccupied site in the crystal structure.

So  Interstitial Atom is not a defect.

c) Point defects include self interstitial atoms, interstitial impurityatoms, substitutional atoms and vacancies. A self interstitialatom is an extra atom that has crowded its way into an interstitial void in the crystal structure.

So Substitutional Atom is also a defect

d) Dislocation is a crystallographic defect or irregularity within a crystal structure.

Therefore the correct answer is (b)