The Vibrational Spectra and Structure of Solid Hydroxylamine and Deutero-Hydroxylamine

Abstract

The infrared spectra of thin films of H2NOH and D2NOD were obtained at — 78° and — 190°C in the region 4000—500 cm—1. Two distinct types of spectra resulted depending on whether the films were formed at — 78° or at — 190°C. The spectra obtained when the films were formed at — 190°C were characterized by broad overlapping bands; those formed at — 78°C gave much narrower bands, some of them splitting into two or more distinct components. The latter type spectrum is representative of the stable crystalline form at low temperature. This spectrum could not be correlated with the amine oxide form of hydroxylamine, NH3→O. Satisfactory vibrational assignments could, however, be made for the model with symmetry of the point group C3, H2NOH. If cis- and trans-rotational isomers coexist in the solid, they must possess very nearly the same potential energy or at least a high potential barrier between them. The O–H stretching vibration in the solid is found at a very low frequency, 2867 cm—1, indicating a very strong hydrogen-type bond with energy of about 13 kcal per mole.