In this paper, the concept of bonding energy Eb was proposed and used as the criterion of the bond character of MO and the strength of chem. bond between atoms in a mol. It's different from Mulliken's overlap population criterion Pb that both of the energy factor of AOs and the overlap factor between AOs are included in Eb. From the results of calcns. of Pb and Eb for a great no. of mols., it was shown that the bonding energy criterion is as good as the Mulliken's overlap population criterion qual., and is better than that quant.f

Key words: MOLECULAR ORBIT, CHEMICAL BONDS, BONDING, ENERGY