The Near Infra-Red Absorption Spectra of Some Halogen Derivatives of Ethane

The infra-red absorption spectra of the following derivatives of ethane, ${\mathrm{C}}_2$${\mathrm{H}}_5$Br, ${\mathrm{C}}_2$${\mathrm{H}}_5$I, C${\mathrm{H}}_2$Cl·C${\mathrm{H}}_2$Cl, C${\mathrm{H}}_2$Cl·C${\mathrm{H}}_2$Br, C${\mathrm{H}}_2$Br·C${\mathrm{H}}_2$Br, C${\mathrm{H}}_3$·CH${\mathrm{Cl}}_2$, C${\mathrm{H}}_3$·CH${\mathrm{Br}}_2$, C${\mathrm{H}}_2$Cl·CH${\mathrm{Cl}}_2$, CH${\mathrm{Cl}}_2$·CH${\mathrm{Cl}}_2$, C${\mathrm{Cl}}_3$·CH${\mathrm{Cl}}_2$, C${\mathrm{Cl}}_3$·C${\mathrm{Cl}}_3$, C${\mathrm{Cl}}_2$·C${\mathrm{Cl}}_2$, CH${\mathrm{Br}}_2$·CH${\mathrm{Br}}_2$, CHCl·CHCl, between 0.8μ and 3μ by means of two different spectrometers, one using a grating of 2500 lines per inch and the other using a grating of 10000 lines per inch. Tables listing spectrometer settings, wave-lengths and wave-numbers are included. A large number of new absorption bands were discovered. It was found that for substances containing no hydrogen no bands existed in the region under investigation. For other substances there was a close similarity in the spectra, particularly where the halogens were interchanged. The bands do not lend themselves to arrangement in a single series, nor does any quantitative relationship exist between the bands in any given substances. No explanation of the mechanism producing the absorption is offered.