Bond order is the number of chemical bonds between a pair of atoms. For example, in diatomic nitrogen N=N the bond order is 3, in acetylene H-C=C-H the bond order between the two carbon atoms is also 3, and the C-H bond order is 1. Bond order gives an indication of the stability of a bond. The element with bond order value 0 cannot exist. Those with fractional values exist but are not stable.