Abstract
A sample of meta-autunite (Ca(UO2)2(PO4)2·6-8(H2O)) from a national reference collection was characterised by Raman spectroscopy as a representation of a potential spent nuclear fuel corrosion product. Raman spectra were collected at 457, 532, 633 and 785 nm; all exhibited some fluorescence effects, though to a lesser extent at 785 nm. The phosphate (v2(PO4)3−, v3(PO4)3−, v4(PO4)3−) and uranyl (v1(UO2)2+ and v2(UO2)2+) features could be unambiguously assigned in the resolved 785 nm spectrum. The position of the v3(UO2)2+ mode was predicted but not observed. The uranyl bond lengths and force constants were determined from the v1(UO2)2+ dominant and shoulder peak, as 1.78±0.01 and 1.79±0.01 Å and 5.69±0.08 and 5.29±0.08 millidynes Å−1, respectively.