Uses and limitations

Tabulated values of bond enthalpies can be employed to estimate the enthalpy of formation of hypothetical compounds. Such type of estimates should be considered as rough and not quantitatively reliable according to the the assumptions of additivity and transfer ability that underlie these calculations are not correct.

Trends in stability or structure of related compounds can frequently be usefully rationalized from bond strength trends. The refuse in B(E-H) according to the a main group is descended leads to reduced thermodynamic  stability of hydrides EH_n. Double-bonded structures are greatly commoner with the elements C, N and O than with others in similar group. The stability of O₂ (double  bonds) versus S₈ (single bonds) can be rationalized from the reality that B(O=O) is more  than two times as large as B(O-O) but similar is not right of sulfur. In a identical way we have CO₂  (molecular with C=O) and SiO₂  (polymeric with single Si-O). The formation of multiple bonds is one of the main issues leading to differences in chemistry between 2p series elements  and those in lower  periods. With valence state Changes are significant in understanding the stability of 'hypervalent' compounds. So SH₄ and SH₆ are unknown, where they would be thermodynamically stable compounds if their S-H bonds were as stronger as in H₂S. The general formation of fluorides in high valency states (example SF₆, IF₇) can be understood from a combination of factors.  The F-F bond is itself rather weak, E-F bonds are generally strong, and they decline less quickly with increasing n in EFn molecules than in other compounds.