File:Chapter 15 - PREDICTION OF BOND ANGLE OF POLYATOMIC MOLECULES pp 144-147.pdf

The angle between the two covalent bonds of a molecule is called the bond angle. When in covalent bonds, bond pair electron clouds, are adjacent to each other, then, due to excessive repulsive force between two adjacent bond pair electron clouds, the bond angle increases. When bond pair electron clouds move towards the central atom instead of the peripheral atom, then, they are adjacent to each other and exhibit much more repulsive force, which increases the bond angle of the molecule. So, the mainly responsible repulsive force for bond angle prediction is a bond pair – bond-pair (BP-BP) repulsion. If there is any other repulsive force greater than BP-BP repulsions, such as lone pair-lone pair (LP-LP) or lone pair-bond pair (LP-BP) repulsion, in this particular case, BP-BP repulsion not freely act, hence, bond angle diminishes