The Dependence of Bond Energy on Bond Length

It is suggested that in a series of similar bonds the bond energy is proportional to the reciprocal of the equilibrium interatomic distance (the bond length). This relation is supported by experimental values for some sequences, such as O_2, S_2, Se_2, Te_2. Application of the relation to other sequences is shown to support the values 170 kcal./mole for the heat of dissociation of N_2 and 139 kcal./mole for the heat of sublimation of carbon. The dependence of bond energy on other factors, including character of bond orbitals, energy of resonance of bonds among alternative positions, and repulsion of unshared electron pairs on the bonded atoms, is discussed.