Infrared spectra of matrix-isolated uranium oxide species. II. Spectral interpretation and structure of UO3

The midinfrared spectra of matrix-isolated UO3 and its oxygen-18 isotopes have been successfully interpreted in terms of a C2ν T-shaped structure. Values of the two bond-stretching and two bond-interaction force constants determined by a normal coordinate analysis using 13 observed frequencies reproduce all peaks in the observed spectrum to within ± 0.6 cm−1. The following assignments for U16O3 species trapped in argon matrices have been obtained: ν1(A1) = 843.50, ν2(A1) = 745.65, ν4(B1) = 852.60 cm−1. The structure and intensity distribution are discussed in terms of current bonding theory for uranyl compounds.