Infra-Red Spectrum of Hexadeuterobenzene and the Structure of Benzene

IN our letter in NATURE of June 22 (p. 1033), we referred inter alia to our measurements of the Raman and infra-red spectra of C 6 D 6 , but did not give the infra-red results, as a collective publication of this and other spectra was projected. In the August number of the Journal of Chemical Physics (p. 446), Barnes and Brattain have now reported some infra-red measurements 1 , and we therefore cite our own data for comparison. The principal frequencies (cm. 1 ) are in Table 1, but we omit the record here of the numerous very weak bands, obviously combination tones, which form an almost continuous background to the spectrum. Intensities are roughly indicated by asterisks. Our complete map of the spectrum shows much less background than appears in Barnes and Brattain's graph, but except for this and the deviations in the extreme frequencies, the agreement is good so far as the ranges overlap.