Sigma bond: “
Pi Bond: “A covalent bond formed by a sidewise overlap of ‘p’ orbitals of atoms that are already bonded through a – bond, and in which the electron clouds are present above and below the internuclear axis is known as π – bond”.
Difference between Sigma bond and Pi bond
| Sigma bond ( |
Pi bond ( |
|---|---|
| This is formed due to the overlap of pure s – s; s – p ; p – p (or) hybrid orbitals of two atoms along their internuclear axis. | This bond is formed due to lateral or sidewise or parallel overlapping of pure ‘p’ orbitals of two atoms. |
| It is a strong bond. | It is a weak bond. |
| These are less reactive. | These are highly reactive. |
| The electron cloud is symmetrical to the line joining the nuclei of the two atoms. | The electron cloud lies above and below the plane of the line joining the atoms. |
| Free rotation of atoms is possible. | Free rotation is not possible. |
| The lobe participating in the overlapping is stretched and the other lobe is reduced. | Both lobes take part in bonding and remain the same in size. |
| It is also called a localized bond. | It is a non-localized bond. |
| It has independent existence. | It forms only after the formation of ‘ |