title: Stability of peroxide-containing uranyl minerals.
abstract: Minerals containing peroxide are limited to studtite, (UO2)O2(H2O)4, and metastudtite, (UO2)O2(H2O)2. High-temperature oxide-melt solution calorimetry and solubility measurements for studtite (standard enthalpy of formation at 298 kelvin is -2344.7 +/- 4.0 kilojoules per mole from the elements) establishes that these phases are stable in peroxide-bearing environments, even at low H2O2 concentrations. Natural radioactivity in a uranium deposit, or the radioactivity of nuclear waste, can create sufficient H2O2 by alpha radiolysis of water for studtite formation. Studtite and metastudtite may be important alteration phases of nuclear waste in a geological repository and of spent fuel under any long-term storage, possibly at the expense of the commonly expected uranyl oxide hydrates and uranyl silicates.
authors: Department of Civil Engineering and Geological Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556, USA.
authors: Karrie-Ann Hughes
authors: KA
authors: Kubatko
authors: Katheryn B
authors: KB
authors: Helean
authors: Alexandra
authors: A
authors: Navrotsky
authors: Peter C
authors: PC
authors: Burns