Regular Geometries and Deviation from Regular Geometries.

The concept of regular and deviation from regular geometries is based on VSEPR theory . According to this theory , we take only the number of electron pairs present in the valence shell of the central atom and these number of electron pairs decided the geometry of molecule

Defination:-

Regular Geometries - The molecules in which the central atom is surrounded only by similar bonded electron pairs have Regular Geometries .

Irregular Geometries - The molecules in which the central atom is surrounded by bond pairs as well as lone pairs have Irregular Geometries .

Molecules such as CH4 , BF3 , PF5 , SF6 , etc. Have regular geometries because the central atom in these molecules are bonded to similar atoms and there are no lone pairs in these molecules .

Molecules such as CHCl3 , CH2Cl2 , etc. in which the central atom is bonded to different atoms and the molecules such as NH3 and H2O which have lone pairs as well as bond pairs , have irregular geometries. 

The results obtained on the basis VSEPR theory are quite similar in arrangement with those obtained from hybridisation concept .

This was simple concept of Regular Geometries and deviation from Regular Geometries . 

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