The Infrared Absorption of Hydrogen Chloride in Nonionizing Solvents

The infrared absorption of hydrogen chloride in four nonionizing solvents has been measured. In every solution studied the HCl fundamental vibrational frequency was found to be lower than for the gas. The variation in frequency was found to increase regularly with dipole moment of solvent when the solvents employed were of the same chemical nature. Solvents of the benzene type were used, and it was found that the displacement of the 3.4μ band approached no limiting value even when a solvent of dipole moment 4.20×${10}^{-18\mathrm{}}$ e.s.u. was used. The results obtained were attributed to the combined effects of dipole interaction and the formation of complexes.