Three-dimensional framework of uranium-centered polyhedra with non-intersecting channels in the uranyl oxy-vanadates A{sub 2}(UO{sub 2}){sub 3}(VO{sub 4}){sub 2}O (A=Li, Na)

Journal Article · Thu Mar 15 04:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2006.12.014· OSTI ID:21015723

Duvieubourg, L ^[1]; Dion, C ^[1]; Abraham, F ^[1]

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1. Unite de Catalyse et de Chimie du Solide, UCCS UMR CNRS 8181, ENSCL-USTL, B.P. 90108, 59652 Villeneuve d'Ascq Cedex (France)

The uranyl vanadates A{sub 2}(UO{sub 2}){sub 3}(VO{sub 4}){sub 2}O (A=Li, Na) have been synthesized by solid-state reaction and the structure of the Li compound was solved from single-crystal X-ray diffraction. The crystal structure is built from {sub {infinity}}{sup 1}[UO{sub 5}]{sup 4{sup -}} chains of edge-shared U(2)O{sub 7} pentagonal bipyramids alternatively parallel to a-vector- and b-vector-axis and further connected together to form a three-dimensional (3-D) arrangement. The perpendicular chains are hung on both sides of a sheet {sub {infinity}}{sup 2}[(UO{sub 2})(VO{sub 4}){sub 2}]{sup 4-} parallel to (001), formed by U(1)O{sub 6} square bipyramids connected by VO{sub 4} tetrahedra, and derived from the autunite-type sheet. The resulting 3-D framework creates non-intersecting channels running down the a-vector- and b-vector-axis formed by empty face-shared oxygen octahedra, the Li{sup +} ions are displaced from the center of the channels and occupy the middle of one edge of the common face. The peculiar position of the Li{sup +} ion together with the full occupancy explain the low conductivity of Li{sub 2}(UO{sub 2}){sub 3}(VO{sub 4}){sub 2}O compared with that of Na(UO{sub 2}){sub 4}(VO{sub 4}){sub 3} containing the same type of channels half occupied by Na{sup +} ions in the octahedral sites. Crystallographic data for Li{sub 2}(UO{sub 2}){sub 3}(VO{sub 4}){sub 2}O: tetragonal, space group I41/amd, a=7.3303(5)A, c=24.653(3)A, V=1324.7(2)A{sup 3}, Z=4, {rho}{sub mes}=5.32(2)g/cm{sup 3}, {rho}{sub cal}=5.36(3)g/cm{sup 3}, full-matrix least-squares refinement basis on F{sup 2} yielded, R{sub 1}=0.032, wR{sub 2}=0.085 for 37 refined parameters with 364 independent reflections with I>=2{sigma}(I)

• OSTI ID: 21015723
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 3 Vol. 180; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CRYSTALLOGRAPHY
LEAST SQUARE FIT
LITHIUM COMPOUNDS
LITHIUM IONS
MONOCRYSTALS
SODIUM COMPOUNDS
SODIUM IONS
SPACE GROUPS
SYNTHESIS
TETRAGONAL LATTICES
URANYL COMPOUNDS
VANADATES
X-RAY DIFFRACTION