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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When a cation approaches an anion, the electron cloud of the anion is attracted towards a cation and hence gets distorted.
bond – What is Fajans rule? – Chemistry Stack Exchange
The effect is called polarisation of the anion. The greater is the polarisation produced, more is the neutralisation of the charges and hence the gules character decreases or the covalent character increases. The polarising power of the cation and the polarisability of the anion and hence the formation of covalent bond depends on:.
Covalent character of lithium halides is in the order:. Larger the charge on the cation, greater fajanz its polarising power.
Hence covalent character increases. If two cations have the same size and charge, then the one with 18 electrons in the outermost shell has greater polarising power than the other with 8 electrons in the outermost shell. The covalent compounds exist in all the three states i.
The crystal structure of covalent compounds differ from that of ionic compounds.
Fajans’ rules – Wikipedia
They usually consists of molecules rather than ions. Covalent compounds have low melting rule boiling point because the molecules in covalent compounds are held together less rigidly.
They are generally soluble in organic solvents but insoluble in water and other tajans solvents. Since there are no free ions in covalent compounds to conduct electricity, they are bad conductors of electricity.
These compounds are molecular in nature and not ionic, their reactions are molecular and proceed at a much slower rate than those of ionic compounds. As the atoms in covalent compounds are held together by the shared electrons ,it is rigid and directional. Hence, atoms in a molecule can take up different directional arrangement and thus show structural and stereoisomerism.
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