Crystal Structure of the (Mg,Fe)[UO₂(P,As)O₄]₂ 10H₂O Solid
SolutionA Novel Mineral Variety of Saleite

O. V. Yakubovich^a, I. M. Steele^b, D. Atencio^c, L. A. Menezes^c, and N. V. Chukanov^d

^a Faculty of Geology, Moscow State University, Moscow, 119992 Russia

e-mail: yakubol@geol.msu.ru

^b The University of Chicago, 5555 South Ellis Avenue, Chicago, IL 60637, United States

^c Universidade de Sáo Paulo, Rua do Lago 562, So Paulo, Brazil

^d Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow oblast, 142432 Russia

Received December 29, 2007

Abstract—The crystal structure of a novel variety {[(Mg_0.81Fe_0.19)(H₂O)₆](H₂O)₄}{(UO₂)[(P_0.67As_0.33)O₄]}₂
of the mineral saléeite is determined using X-ray diffraction (Bruker Smart diffractometer, MoK, graphite
monochromator, 2_max = 56.62°, R = 0.0321 for 2317 reflections, T = 100 K). The main crystal data are as fol-
lows: a = 6.952(6) Å, b = 19.865(5) Å, c = 6.969(2) Å, = 90.806(4), space group P12₁/n1, Z = 2, and _calcd =
3.34g/cm³. It is shown that the structure is formed by alternating (along the [010] direction) anionic layers,
which are composed of uranium bipyramids and T(P,As) tetrahedra, and cation layers consisting of M(Mg,Fe)
octahedra and water molecules, which are joined through a system of asymmetric hydrogen bonds. The hydro-
gen atoms are located, the scheme of hydrogen bonds is established, and their geometric characteristics are cal-
culated.

PACS numbers: 61.10.Nz

DOI: 10.1134/S1063774508050064

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