||Formation of multiple bonds
||The two bonds in a carbon-carbon double bond are quite different in their origin. Observe how the multiple bonds are formed in ethylene and acetylene.
||The two bonds involved in a carbon-carbon double bond are quite different. One of the bonds, known as the sigma bond, involves the physical overlap of two hybrid orbitals. The other bond, known as a pi bond, involves side to side overlap of unhybridized atomic p orbitals.
||ethylene, acetylene, ethene, ethyne, pi bond, sigma bond