Difference between Schottky and Frenkel Defects
| S. No | Schottky | Frenkel |
| 1 | These defects arise in a crystal when the same number of cations and anions are missing from their normal lattice site and as a result, a pair of holes are formed. | These defects arise in a crystal due to the presence of a hole in the cationic lattice site and cation occupies an interstitial position. |
| 2 | This defect lowers the density of the crystal. | This defect does not change the density of the solid. |
| 3 | These defects are generally present in highly ionic solids that have high coordination number and in which cations and anions are almost of similar sizes. E.g., NaCl, CsCl. | These defects are generally present in ionic solids which have low coordination number and whose anions are much larger in size than cations. E.g., AgCl, AgBr, ZnS. |
Read About
Shottky Effect
Frenkel Effect
Non-Stoichiometric Defects
Non-Stoichiometric compounds are those in which the number of positive and negative ions are not in the same ratio as indicated by their chemical formulae.
Examples are– Fe0.95O, Cu1.97S and VOx, where x ranges from 0.6-1.3.
The point defects that disturb the stoichiometry of the compound are called Non-Stoichiometry defects.
Metal excess Defects
Extra cations occupying the interstitial sites. When a cation and an electron of some non-metal atom occupy interstitial positions in the lattice with complete cationic and anionic lattices, the defect is called a Metal Excess defect due to interstitial cations.
When a negative ion is missing from its lattice site and in its vacancy, an electron associated previously with it is left, the defect is called Metal Excess Defect due to anion vacancies.
Metal Deficiency Defects
When a cation is missing from its lattice site and adjacent metal ion acquires higher oxidation state, the defect is called Metal Deficiency Defect due to cation vacancies.
Cation vacancies in some crystals make them good catalysts. This is because the positive charge due to missing cation is balanced by an adjacent ion having charge which leads to.
Difference Between Metal Excess Defect and Frenkel Defect
| S.No. | Metal Excess Defect | Frenkel Defect |
| 1 | It has no holes in the crystal lattice. | It has holes in crystal lattice. |
| 2 | It has interstitial electrons. | It has no interstitial electrons. |
Difference Between Metal Excess Defect and Schottky Defect
| S.No. | Metal Excess Defect | Schottky Defect |
| 1 | In this type of defect, there are holes in the crystal lattice, due to missing a negative ion from the lattice site. | Crystal lattice has a pair of holes due to missing of a cation and anion from their normal lattice site. |
| 2 | Holes are occupied by free electrons. | Holes are not occupied by free electrons. |
Impurity Defect
If a foreign atom or ion as impurity occupies a lattice site, the defect is called impurity defect. If the foreign atom or ion occupies voids in the structure, the defect is called interstitial impurity defect.
Impurity defects in ionic crystals can be introduced by adding impurity of ions. If the impurity ions are in a different valence state from that of the host ions, vacancies are created.
For Example-
Addition of CdCl2 to AgCl yields solid solutions in which the divalent Cd occupies the Ag sites.
These cation vacancies result in higher conductivity of the solid.
Introduction of defects by incorporating a small amount of foreign impurity in the host crystal is called DOPING.
You May Also Like-
What are imperfection or defects of Solids
What Do you know about Solid State?
What do you know about Solid Waste??
Processing of solid waste and On-site Handling by engineering System
What do you know about Hazardous Waste??
Landfill Disposal of Solid Waste
Right Understanding
Right Understanding We all know that the Human Desire is to be in continuous happiness which is the need of I (self). But do you know, from where Continuous happiness will come? No, right! So continuous happiness is to be in Right Understanding, Right Feeling, and Right Thought that is Activity of I (Self). Do…
Where We Are
Where We Are (Self-Evolution) We exist as human being. We want to live a fulfilling life. We have some desires and we have some programs for the fulfilment of it. We need to understand our basic aspiration and program for its fulfillment correctly and comprehensively. Only then, we can ensure fulfillment. We should explore ourselves…
Highway Construction
Highway Construction Embankment Construction Materials and General Requirements The materials used in embankments, subgrades, earthen, shoulders, and miscellaneous backfills shall be soil, moorum, gravel, a mixture of these. Clay having liquid limit exceeding 70 and plasticity index exceeding 45; shall be considered unsuitable for embankment. Sub-grade and top 500mm portion of the embankment just below…
Special Concretes
Special Concretes Concrete is most vital material in modern construction. In addition to normal concrete, other varieties in use are, high strength and high-performance concrete, self-compacting, lightweight, high density, fiber reinforced, polymer, colored concrete, etc. The making of concrete is an art as well as a science. Special types of concrete are those with out-of-the-ordinary…
Marketing Practices
Marketing Practices Success in the world of business, no matter how you earn it, you have to rule on the marketplace. Although luck plays a role in the outcome of the market strategies. In the business decisions, there should be the understanding of market otherwise the failure will take place by the marked decisions. While…
Risk Analysis
Risk Analysis The risk that remains after the implementation of controls is called the residual risk. All systems will have residual risk because it is virtually impossible to completely eliminate risk to an IT system. In other words, we can say that there are two main parts of the security risk analysis known as Quantitative…
