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.