Intercalation reactions of the neptunyl(VI) dication with hydrogen uranyl phosphate and hydrogen neptunyl phosphate host lattices

• Published in: Inorganic chemistry 1989-07, Vol.28 (15), p.2926-2930
• Main Authors: Dorhout, Peter K, Kissane, Richard J, Abney, Kent D, Avens, Larry R, Eller, P. Gary, Ellis, Arthur B
• Format: Article
• Language: English
• Subjects: 400702 - Radiochemistry & Nuclear Chemistry- Properties of Radioactive Materials; ACTINIDE COMPOUNDS; Chemistry; CLATHRATES; CRYSTAL STRUCTURE; DATA; Exact sciences and technology; EXPERIMENTAL DATA; INFORMATION; Inorganic chemistry and origins of life; MOLECULAR STRUCTURE; NEPTUNIUM COMPOUNDS; NEPTUNIUM PHOSPHATES; NUMERICAL DATA; OXYGEN COMPOUNDS; PHOSPHATES; PHOSPHORUS COMPOUNDS; Preparations and properties; RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; Salts; TRANSURANIUM COMPOUNDS; URANIUM COMPOUNDS; URANYL COMPOUNDS; URANYL PHOSPHATES
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic00314a011

The hydrated layered solids hydrogen uranyl phosphate, HUO{sub 2}PO{sub 4}, HUP, and its isostructural neptunyl analogue, HNpO{sub 2}PO{sub 4}, HNpP, can be intercalated with UO{sub 2}{sup 2+} and NpO{sub 2}{sup 2+} ions to yield a family of layered, hydrated solids that have been characterized by x-ray powder diffraction and by infrared, Raman, and electronic spectroscopy. Aqueous reactions of HUP with UO{sub 2}{sup 2+} and HNpP with NpO{sub 2}{sup 2+} lead to hydrated layered solids (UO{sub 2}){sub 3}(PO{sub 4}){sub 2}, UP, and (NpO{sub 2}){sub 3}(PO{sub 4}){sub 2}, NpP; preparation of UP from HUP and of NpP from HNpP can also be effected by thermal decomposition of the parent solids, thus affording a set of self-intercalation reactions that are reversible. Cross-intercalation reactions (UO{sub 2}{sup 2+} into HNpP; NpO{sub 2}{sup 2+} into HUP) also proceed under stoichiometric conditions. Conducting the cross-intercalation reactions with high concentrations of intercalating ion leads to substantial substitution of actinyl ions in the host lattice sheets. The intercalation reactions of HUP and HNpP are shown to be selective by the marked preference found for intercalating Np(VI) over Np(V), as evidenced by the lack of reactivity of NpO{sub 2}{sup +} toward either host. Characterization by x-ray powder diffraction revealed that all of the solids could be indexed on the basis of tetragonal unit cells; the a lattice constant is {approx} 6.95 {angstrom} in all samples, but intercalation of actinyl ions increases the interlamellar spacing, c/2, from {approx} 8.7 {angstrom} in HUP and HNpP to {approx} 11.2 {angstrom}. Vibrational and optical properties of the intercalated solids are derived from transitions characteristic of the actinyl ions comprising the solids. 24 refs., 5 figs., 1 tab.