Calorimetric investigations on stoichiometric barium and uranium oxides

Heat capacities and enthalpy increments of barium uranates: BaU2O7(s), Ba2U3O11(s), Ba2.875UO5.875(s) and Ba3UO6(s) were measured using a differential scanning calorimeter and a high-temperature Calvet calorimeter. The heat capacities and enthalpy increments were measured in the temperature range 126–304 K and 299–1011 K, respectively. A set of self consistent thermodynamic functions such as entropy, Gibbs energy function, heat capacity and Gibbs energy and enthalpy of formation values for BaU2O7(s), Ba2U3O11(s), Ba2.875UO5.875(s) and Ba3UO6(s) have been computed for the first time using the data obtained in the present study and other available experimental data.