Thermodynamic data of compounds and complexes of U, Np, Pu and Am with selected organic ligands

A comprehensive literature review of thermodynamic data for compounds and complexes of actinides with oxalate, citrate, ethylene-diamine-tetra-acetate (EDTA) and α-iso-saccharinate has been carried out within the scope of the Thermodynamic Data Base project of the Organisation for Economic Co-operation and Development - Nuclear Energy Agency (OECD/NEA). Reliable values could be selected mainly for Am(III), Np(V) and U(VI) complexes, whereas serious data gaps were found for the tetravalent actinides. The redox states U(III), U(V), Pu(V), Am(V), Np(VI), Pu(VI) and Am(VI) are unstable in the presence of the selected organic ligands. Missing or unreliable data in these unstable redox states are of no importance from the viewpoint of application in environmental modelling studies. (authors)