An FTIR investigation of co-condensed nitrous oxide, acetylene mixtures. Evidence for two phases with the formula N2O·C2H2

The infrared spectra of co-condensed nitrous oxide and acetylene are reported. It is shown, from these spectra that, in addition to crystalline nitrous oxide and acetylene, two further crystalline phases, each having the stoichiometry N2O·C2H2, are formed. When cooling rates are high the less stable of these phases can be the only phase formed: however, at slower rates of cooling the more thermodynamically stable phase predominates. It is argued that the two phases differ in the relative orientations of the dipole moments of the constituent nitrous oxide molecules.