The trend of attaining covalent character by ionic compounds as a consequence of polarisation may be generalized in terms of Fajan’s rule. According to this. Fajans’ Rule for the prediction of relative nonpolar character. Electrostatic forces in a crystal Learn Fajans’ Rule by Disclosing Covalent Characteristics in Ionic. Fajan Rule: Greater is the polarization, greater is the covalent character. | Online Chemistry tutorial IIT, CBSE Chemistry, ICSE Chemistry, engineering and.

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The large charge pulls on the electron cloud of the iodines. What Is Valence Bond Theory.

Fajans’ rules – Wikipedia

What is Fajans rule? From this it is possible to calculate a theoretical dipole moment for the KBr molecule, assuming opposite charges of one fundamental unit located at each nucleus, and hence the percentage ionic character of KBr.

They can be summarized in the following table: Die Eigenschaften salzartiger Verbindungen und Atombau”. Since there are no free ions in covalent compounds to conduct electricity, they are bad conductors of electricity. This means a comparison needs to be made between a noble gas core and pseudo noble gas core, which as noted above holds that the faajns noble gas would be the more polarizing.


As the electron cloud of the iodine nears the aluminium atom, the negative charge of the electron cloud “cancels” out the positive charge of the aluminium cation. From Wikipedia, the free encyclopedia.

Fajans’ rules – Oxford Reference

They usually consists of molecules rather than ions. In this case, the aluminium ion’s charge will “tug” on the electron cloud of iodine, drawing it closer to itself. Login to track and save your performance.

Fajans’ rules note the difference were formulated in by Kazimierz Fajans. In inorganic chemistryFajans’ rulesformulated by Kazimierz Fajans incajans [2] [3] are used to predict whether a chemical bond will be covalent or ionicand depend on the charge on the cation and the relative sizes of the cation and anion.

Fajans’ rules

They can be summarized in the following table:. Practise s of questions mapped to your syllabus. In general they increase with increasing rulex number. The various types of these interactions span large differences in energy and for the halogens and interhalogens are generally quite small. Here the significant difference between the cations is in their electronic configurations.

The polarising power of the cation and the polarisability of the anion and hence the formation of covalent bond depends on:. In this article, we are going to discuss covalent characteristics in ionic bonds. When two molecules are close together, the instantaneous dipole of one molecule can induce a dipole in the second molecule.


Let us consider AlI 3 ; this is an ionic bond which was formed by transfer of electrons.

Fajan’s Rules

By Fajans’ Rules, compounds are more likely to be ionic if: The changes seen in the variation of MP and BP for the dihalogens and binary interhalogens can be attributed to the increase in the London dispersion forces of attraction between the molecules. When more molecules interact these induced dipoles lead to intermolecular attraction.

Comments Rlues is very helpful thak u very much!!! For help asking a good homework question, see: In the time with the help of X-ray crystallography, he was able to predict ionic or covalent bonding with the attributes like ionic and atomic radius. Jj Thomson Atomic Theory. They are derived from momentary oscillations of electron charge in atoms and hence are present between all particles atoms, ions and molecules. Electronic configuration of the cation: Boiling Point Of Oxygen.

Leave a Reply Cancel reply Your email address will not be published. The covalent character is found in compounds which have high polarizing cation and high polarizable anion.