Uranyl silicates are an important group of U(VI) minerals. The chemistry of materials containing U(V) is considerably less developed owing to the tendency of U5+ to either oxidize to U6+ or disproportionate to U4+ and U6+. We have recently synthesized several U(V) silicates and germanates by a hydrothermal method at ca. 600 �C and 170 MPa. A number of mixed-valence compounds have also been synthesized, for example, a mixed-valence uranium(IV,V) silicate, Cs2K(UO)2Si4O12, uranium(IV,VI) germinate, Cs8U(UO2)3(Ge3O9)3�3H2O, uranium(V,VI) germanates, A3(U2O4)Ge2O7 (A = Rb, Cs), and a uranium(IV,V,VI) silicate, Na7UIVO2(UVO)2(UV/VIO2)2Si4O16, in which three oxidation states of uranium co-exist in one compound. All members in the family of uranium silicates and germanates with the oxidation states of uranium from +4 to +6 have been observed. Their crystal structures, XPS and EPR spectroscopy studies will be presented.

High-temperature, high-pressure hydrothemal synhesis, crystal structures and spectroscopy studies of uranium(V) and mixed-valence uranium silicates and germanates

244th National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.