Orbital hybridization is the mixing of the outer shell orbitals in an atom in order for it to be able to complete the octet rule. For carbon, this means that the electrons in the 2s, 2px, 2py, and 2pz combine to form new, equivalent orbitals. If the carbon atom only forms single bonds, sp3 hybridization produces four equal orbitals. If a double bond is formed, sp2 hybridization produces three equal orbitals, with a single 2p orbital left to form the second part of the double bond. If a triple bond is formed, sp 2s, 2p x, 2p y, and 2p z combine to form new, equivalent orbitals. If the carbon atom only forms single bonds, s p three hybridization produces four equal orbitals. If a double bond is formed, s p two hybridization produces three equal orbitals, with a single 2p orbital left to form the second part of the double bond. If a triple bond is formed, s p hybridization produces 2 equal orbitals, with two 2p orbitals left to form the second and third part of the double bonds.
When carbon forms bonds with hybridized orbitals, the bond is a σ (sigma) bond. The bonds formed with unhybridized orbitals for the remaining part of double or triple bonds are called π sigma(sigma) bond. The bonds formed with unhybridized orbitals for the remaining part of double or triple bonds are called pi (pi) bonds.