| Schottky Defect | Frenkel Defect |
| Schottky defect occurs in those ionic crystals where difference in size between cation and anion is small. | Frenkel defect usually occurs in those ionic crystals where size of anion is quite large as compared to that of the cation. |
| In Schottky defect, both cation and anion leave the solid crystal. | In Frenkel defect, only the smaller ion (cation) leaves its original lattice site; whereas, the anion remains in original lattice sites. |
| The atoms permanently leave the crystal. | Here, atoms leave the original lattice site and occupy interstitial position. So atoms reside within the solid crystal. |
| One Schottky defect leads to the formation of two vacancies. | One Frenkel defect creates one vacancy and one self-interstitial defect. |
| Two atoms reduce from the crystal for each Schottky defect. | The number of atoms present in the crystal before and after Frenkel defect remains same. |
| Due to vacancy formation, Schottky defect reduces density of the solid. | Density of the solid crystal before and after Frenkel defect remains same as no atom leaves the solid. |
Common materials where Schottky defect can be found are:
(a) Sodium Chloride (NaCl)
(b) Potassium Chloride (KCl)
(c) Potassium Bromide (KBr)
(d) Silver Bromide (AgBr)
(e) Cerium Dioxide (CeO2)
(f) Thorium Dioxide (ThO2) | Common materials where Frenkel defect can be found are:
(a) Zinc Sulfide (ZnS)
(b) Silver Chloride (AgCl)
(c) Silver Bromide (AgBr) |
