Infrared Spectra of Some Unstable Isomers of N2O4 and N2O3

The temperature dependence of the infrared spectra of N2O4 and N2O3 in the solid phase at liquid-nitrogen temperatures has been investigated. From these spectra of both 14N and 15N isotopic molecules, absorption bands which may be assigned to unstable isomers of these nitrogen oxides have been identified. A reasonable interpretation of these absorption bands can be made by assuming the existence of two unstable forms of N2O4 and one of N2O3.