Short communication: The Raman fingerprint of U3O7

In this work, stoichiometric U3O7 (i.e., UO2.33) has been prepared, its stoichiometry and structure confirmed by TGA and XRD, respectively, and its Raman fingerprint described for the first time. To validate the analysis, this UO2.33 specimen has been compared with two less-oxidized samples, namely UO2.28 and UO2.31. In addition to the known Raman bands of UO2+x structures, new features obtained at 328 cm-1 (B1g stretching mode), 432 and 509 cm-1 (splitting of the T2g mode due to symmetry loss), and 671 cm-1 (likely indicative of a very substantial oxygen sublattice distortion) have been found to be distinctive of U3O7.