RAMAN SPECTROSCOPIC INVESTIGATION OF URANYL SULFATE MINERALS

Uranyl sulfates are important constituents of uranium ores and represent a significant population of U(VI) minerals discovered in recent years due to their propensity to form in mine tailings and legacy sites related to uranium exploration. Recently, we surveyed all available Raman spectra for uranium minerals, and found significantly less available data for uranyl sulfates relative to other groups of uranium minerals. In that work, we described average spectra for groups of uranyl minerals towards understanding common vibrational spectroscopic features that are attributable to similarities in oxyanion chemistry amongst U(VI) minerals, yet we were only able to include data for three uranyl sulfate minerals. To increase understanding of this group of minerals, we have collected Raman spectra for seventeen species of natural uranyl sulfate minerals. Towards increasing our understanding of underlying structural and chemical features which give rise to spectroscopic observables, we relate here differences in structure type, charge balancing cation, and locality of origin to features observed in the Raman spectra of select natural uranyl sulfates.