A molecular orbital theory of hydrocarbons

The molecular orbital theory of hydrocarbons developed in a previous paper [1] has been extended and applied to the molecules ethane, ethylene and acetylene, enabling the long-range bond orders, and hence the extent of the delocalization of electrons between σ bonds, to be compared for the three hybridizations sp3, sp2 and sp. It is found that the geminal bond orders are sensitive to changes in hybridization as they depend directly on the s-character of the bonds. Vicinal bond orders are quite large and found to be closely related to the extent of second-order hyperconjugation.