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The Crystal Structure of Ianthinite, a Mixed-Valence Uranium Oxide Hydrate

  • Peter C. Burns (a1), Robert J. Finck (a2), Frank C. Hawthorne (a3), Mark L. Miller (a4) and Rodney C. Ewing (a4)...


Ianthinite, [U4+ 2(UO2)4O6(OH)4(H2O)4](H2O)5, is the only known uranyl oxide hydrate mineral that contains U4+, and it has been proposed that ianthinite may be an important Pu4+ -bearing phase during the oxidative dissolution of spent nuclear fuel. The crystal structure of ianthinite, orthorhombic, a 7.178(2), b 11.473(2), c. 30.39(1) Å, V 2502.7 Å3, Z = 4, space group P2 1 cn, has been solved by direct methods and refined by least-squares methods to an R index of 9.7 % and a wR index of 12.6 % using 888 unique observed [ | F | ≥ 5σ | F | ] reflections. The structure contains both U6+ and U4+. The U6+ cations are present as roughly linear (U6+O2)2+ uranyl ions (Ur) that are in turn coordinated by five O2-and OH located at the equatorial positions of pentagonal bipyramids. The U4+ cations are coordinated by O2-, OH and H2O in a distorted octahedral arrangement. The Urφ5 and U4+φ6 (φ: O2-, OH, H2O) polyhedra link by sharing edges to form two symmetrically distinct sheets at z z ≈ 0.0 and z ≈ 0.25 that are parallel to (001). The sheets have the β-U3O8 sheet anion-topology. There are five symmetrically distinct H2O groups located at z ≈ 0.125 between the sheets of Uφn polyhedra, and the sheets of Uφn polyhedra are linked together only by hydrogen bonding to the intersheet H2O groups. The crystal-chemical requirements of U4+ and Pu4+ are very similar, indicating that extensive Pu4+ ↔ U4+ substitution can occur within the sheets of Uφn polyhedra in the structure of ianthinite.



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[1] Pearcy, E.C., Prikryl, J.D., Murphy, W.M. and Leslie, B.W., Appl. Geochem. 9 (1994) 713.
[2] Deliens, M., Piret, P., and Comblain, G., Les Minéraux Secondaires d'Uranium du Zaïre (Musée Royal de l'Afrique Centrale, Tervuren, Belgium, 1981) 99 pp.
[3] Deliens, M., Bull. Soc. Franc. Minéral. Cristallogr. 100 (1977) 32.
[4] Guillemin, C. and Protas, J., Bull. Soc. Franc. Minéral. Cristallogr. 82 (1959) 80.10.3406/bulmi.1959.5308
[5] Frondel, C., Systematic Mineralogy of Uranium and Thorium. U.S. Geological Society Bulletin 1064 (1958) 400 pp.
[6] Bignand, C., Bull. Soc. Franc. Mineral. Cristallogr. 78 (1955) 1.
[7] Finch, R.J. and Ewing, R.C., Alteration of uraninite in an oxidizing environment and its relevance to the disposal of spent nuclear fuel. SKB Technical Report 91–15 (1991) (SKB, Stockholm).
[8] Finch, R.J. and Ewing, R.C., J. Nucl. Mater. 190 (1992) 133.10.1016/0022-3115(92)90083-W
[9] Johnson, L.H. and Werme, L.O., Mater. Res. Soc. Bull. XIX(12) (1994) 24.
[10] Forsyth, R.S. and Werme, L.O., J. Nucl. Mater. 190 (1992) 3.10.1016/0022-3115(92)90071-R
[11] Wronkiewicz, D.J., Bates, J.K., Gerding, T.J., Veleckis, E. and Tani, B.S., J. Nucl. Mater. 190 (1992) 107.10.1016/0022-3115(92)90081-U
[12] Stroes-Gascoyne, S., Johnson, L.J., Beeley, P.A., and Sellinger, D.M., In: Scientific Basis for Nuclear Waste Management IX (Werme, L.O., ed), Materials Research Society Proceedings Volume 50 (Materials Research Society, Pittsburgh, 1985) 317.
[13] Wang, R. and Katayama, J.B., Nucl. Chem. Waste Management 3 (1982) 83.
[14] Wadsten, T., J. Nucl. Mater. 64 (1977) 315.10.1016/0022-3115(77)90086-1
[15] Ewing, R.C., In: Scientific Basis for Nuclear Waste Management XVI (Interante, C.G. & Pabalan, R.T., eds). Materials Research Society Proceedings, Volume 294 (Materials Research Society, Pittsburgh, 1993) 559.
[16] Bruno, J., Casas, I., Cera, E., Ewing, R.C., Finch, R.J. and Werme, W.O., In: Scientific Basis for Nuclear Waste Management XVIII (Murakami, T. & Ewing, R.C., eds). Materials Research Society Proceedings, Volume 353 (Materials Research Society, Pittsburgh, 1995) 633.
[17] Finch, R. J. and Ewing, R.C., In: Scientific Basis for Nuclear Waste Management XVI (edited by Barkatt, A. and von Konynenburg, R.A.,), Materials Research Society Proceedings Volume 333 (Materials Research Society, Pittsburgh, 1994) 625.
[18] Cordfunke, E.H.P., Prins, G. and van Vlaanderen, P., J. Inorg. Nucl. Chem. 30 (1968) 1745.10.1016/0022-1902(68)80348-3
[19] Taylor, P., Lemire, R.J. and Wood, D.D., In: Proceedings of the Third International Conference on High-Level Radioactive Waste Management, Las Vegas, Nevada (American Nuclear Society, La Grange, IL, and American Society of Civil Engineers, New York, 1992) 1442.
[20] Taylor, P., Wood, D.D., Owen, D. G. and Park, G.-I., J. Nucl. Mater. 183 (1991) 105.
[21] Frondel, J.W. and Cuttita, F., Am. Mineral. 39 (1953) 1018.
[22] Schoep, A. and Stradiot, S., Am. Mineral. 32 (1947) 344.
]23[ Cromer, D.T. and Mann, J.B., Acta Crystallogr., A24 (1968) 321.10.1107/S0567739468000550
[24] Cromer, D.T. and Liberman, D., J. Chem. Phys. 53 (1970) 1891.10.1063/1.1674266
[25] Evans, H.T. Jr., Science, 141 (1963) 154.10.1126/science.141.3576.154
[26] Shannon, R.D., Acta Crystallogr. A32 (1976) 751.10.1107/S0567739476001551
[27] Brese, N.E. and O'Keeffe, M., Acta Crystallogr. B47 (1991) 192.
[28] In prep.
[29] Burns, P.C., Miller, M.L. and Ewing, R.C., Can. Mineral. 34 (1996) 845.
[30] Loopstra, B.O., Acta Crystallogr. B26 (1970) 656.10.1107/S0567740870002935
[31] Pagoaga, M.K., Appleman, D.E. and Stewart, J.M., Am. Mineral. 72 (1987) 1230.
[32] Finch, R.J., Cooper, M.A., Hawthorne, F.C. and Ewing, R.C., Can. Mineral. 34 (1996) (in press)
[33] Piret, P., Bull. Mineral. 108 (1985) 659.
[34] Burns, P.C., Ewing, R.C. and Miller, M.L., J. Nucl. Mater. (1996) (accepted).
[35] Christoph, G.G., Larson, A.C., Eller, P.G., Purson, I.D., Zahrt, J.D., Penneman, R.A. and Rinehart, G.H., Acta Crystallogr. B44 (1988) 575 10.1107/S0108768188008316


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