Infrared Absorption Spectra of Trimethylamine Sulfur Trioxide

The infrared spectra of trimethylamine sulfur trioxide in the solid state have been measured in the region from 4000 cm −1 to 80 cm −1 . Assignments of the observed spectra are made under C 3v symmetry. Calculation of the force constants were carried out by the FG matrix method, assuming the simple valence force field. The force constant of the NS bond is almost equal to that of sulfamic acid. By comparing the force constants with those of the related compounds, it is concluded that trimethylamine sulfur trioxide is a donor‐acceptor complex.