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

•ΔfHo, ΔfGo and So298 thermodynamic data for uranium salts and their hydrates are considered.•Thermodynamic Difference Rule (TDR) applied to estimate and select preferred values.•Generation of missing thermodynamic data using the TDR is the aim of the paper.•The most trusted data has, whenever possible, been identified by the authors.•No structural information is required concerning the compounds studied.

A comprehensive thermodynamic database of experimental standard enthalpy of formation, ΔfHo values, standard free energies of formation, ΔfGo and standard entropies, So298 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.