Molecular and electronic structure of [An.sup.IV][Fe.sup.II][(CN).sub.6]*x[H.sub.2]O (An = Th, U, Np) compounds: an X-ray absorption spectroscopy investigation

[An.sup.IV] [Fe.sup.II] [(CN).sub.6].x[H.sub.2]O (An = Th, U, Np) molecular compounds have been prepared by precipitation from acidic media. These microcrystalline compounds have been characterized by infrared spectroscopy, X-ray diffraction, and X-ray absorption spectroscopy. They have been found to be isostructural with the [Ln.sup.III]K[Fe.sup.II][(CN).sub.6].4[H.sub.2]O compounds. The molecular structures of these compounds are presented and their chemical formulas are given: in all compounds, the Fe[(CN).sub.6] octabedra is conserved and the An ion is linked to the N atoms of the CN ligands. The formal oxidation states are also discussed. Key words: hexacyanoferrate, actinide, EXAFS, XANES, X-ray absorption spectroscopy.