“…In this context, understanding the behaviour of neptunium in the presence of Fe oxyhydroxides, including magnetite and green rust, informs prediction of the long-term behaviour of risk driving radionuclides in engineered and natural environments, including in radioactive waste disposal. Previous studies demonstrate that Np(V) can interact with phases such as ferrihydrite [18][19][20], lepidocrocite [21], goethite [19,20,22], hematite [19,20,23] and magnetite [12,16,20,24]. Here, for Fe(III) containing minerals, Np(V) typically forms inner sphere Np(V) complexes or, in the presence of carbonate, Np(V)-carbonate surface complexes [19,23,25].…”