Actinide ions with sulfate ligands are common in ground and surface waters.They are especially relevant to actinide migration from polluted soils or radioactive waste storage sites into the environment.While structures of An(IV)(SO4)4(H2O)4 are known for U,Np and Pu,no such compounds are reported for the other actinides [1].We have performed theoretical studies on the electronic structure of the model complexes An(SO4H)4(H2O)4 for all the actinides (An = Th – Cm) [2].