Other measures

Thermochemical bond energies may be difficult to determine, either for experimental reasons or due to the limitations within the assumption of transferability that is frequently required. Alternative measures of comparative bond strength that are frequently helpful include the following:

1. The bond length, that for a given pair of elements decreases with increasing strength (example with increasing bond order, like in the sequence N-N 145 pm, N=N 125 pm, N≡N 110 pm); bond length measurements are frequently useful for depicting the presence of metal-metal bonds in transition metal compounds;
2. The bond stretching frequency calculated by vibrational spectroscopy (example IR,) is related to the stretching force constant and gets increases with bond strength; IR measurements have been specifically helpful in the study of CO as a ligand in transition metal carbonyl compounds.