The Assignment of the Vibrational Spectra of Ethyl Mercaptan and the Ethyl Halides, and the Characterization of an SH Deformation Frequency

An assignment is given for all the fundamental modes of vibration of the ethyl mercaptan molecule from the observed vibrational spectra. By analogy the observed frequencies in the spectra of ethyl chloride, bromide, and iodide are also assigned to normal modes of vibration of these molecules. Evidence is presented that one of the deformation modes of the SH linkage in mercaptans has a characteristic frequency lying between the limits of 800 and 900 cm−1. This frequency is usually stronger in the Raman spectrum.