Pi bond is formed as a result of the overlapping of two unhybridized orbitals. The pi-bond exists along with the sigma bond and the rotation of the bond is quite restricted. The strength of the pi-bond is very low as compared to the sigma bond. Pi-bond is formed always after the formation of the sigma bond.
The maximum number of pi-bonds that can be formed between the two atoms is two. The pi-bonds do not exhibit any symmetry around the axis of the bond. They cannot be used in determining the shape of the molecules. The atoms that have pi-bonds in them are not as reactive as those with sigma bonds.
