Knowledge Bank

The most general structure for carboxylic acids in the solid state is that of weakly interacting hydrogen bonded dimeric units. An alternative Structure is a hydrogen bonded polymer. Acetic acid crystallizes in this manner. Therefore, as a part of a continuing study of the structures and interactions of carboxylic acids in the condensed phase, the polarized infrared spectra of acetic acid and two of its deuterated derivatives have been recorded. Factor group analyses for different possible interpretations of the vibrational crystal spectrum will be presented, and consistency of the interpretations with the experimental infrared band polarizations and the known crystal structure will be discussed. The results will be compared with similar analyses performed on hydrogen bonded dimer systems.