The thermodynamics of uranium salts and their hydrates - Estimating thermodynamic properties for nuclear and other actinoid materials using the Thermodynamic Difference Rule (TDR)

A comprehensive thermodynamic database of experimental standard enthalpy of formation, Δ f H o values, standard free energies of formation, Δ f G o and standard entropies, S o 298 for uranium salts and their hydrates at 298 K and 1 bar pressure is assembled. For many of these materials there exist experimental uncertainties or else multiple values (often considerably different) are listed for the same material. The aim of this paper is to showcase the ability of the Thermodynamic Difference Rule (TDR) to provide quite accurate estimates of such data (usually errors are less than 1%) and to provide guidance as to the most trusted value to adopt. In addition, where possible the TDR has been used to estimate missing literature values. New thermochemical data values are predicted and TDR is not reliant on possession of knowledge of crystal structures.