Infrared Spectra of Gaseous and Solid Hydrazoic Acid and Deutero-Hydrazoic Acid: The Thermodynamic Properties of HN3

Abstract

Infrared studies of HN3 and DN3 in the gas and solid phases and of HN3 in CCl4 solutions are presented. The two low-frequency skeletal bending modes are identified, permitting calculation of the thermodynamic properties of hydrazoic acid. Hydrogen bonding of HN3 and DN3 in the solid state is indicated by frequency shifts of the NH and ND stretching motions (216 and 151 cm—1, respectively). No evidence of hydrogen bonding was observed in solutions of HN3 in CCl4 at concentrations up to 0.3 M. An irreversible phase transition is observed on warming solid hydrazoic acid above about 120°K.