Bond order

Bond order is the number of bonds between a pair of atoms. For example in nitrogen N:::N the bond order is 3, in acetylene H:C:::C:H the bond order between the two carbon atoms is 3 and the C:H bond order is 1.

In Molecular Orbital Theory bond order is also defined is the difference between the number of bonding electrons and the number of antibonding electrons, divided by two.

Bond order is an index of bond strength and is used extensively in valence bond theory