Class 11 Chemistry Chemical Bonding Structure Polarization


Ionic bond is formed by transfer of electrons .As a result, the cation and anion are formed .So, cation formed distort the shape of electron cloud of anion as shown in figure:



Distortion of electron cloud of the negatively charged ion by the positively charged ion is called Polarization.

The Extent of polarization:  Is given by Fazan rule

According to Fazan,

  • Smaller the size of ion, more it can distort the electron cloud of other. Hence, more is the polarization.

For example:


  • Larger the size of anion ,more easily it gets distorted.

For example:



  • More is the magnitude of charge: More is the covalent character.

 For Example:- NaCl< CaCl2 < AlCl3

                      (Maximum covalent character in aluminium chloride)

  • Electronic configuration of cation: Cation with 18 electrons in its outermost shell can cause more distortion.

For Example:- Na+ = 1s2, 2s2, 2p6

Cu+ = 1s2,2s2,2p6,3s2,3p6,4s1,3d10

Out of NaCl and CuCl, the latter has more covalent character.   


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