skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The A{sub 1-x}UNbO{sub 6-x/2} compounds (x=0, A=Li, Na, K, Cs and x=0.5, A=Rb, Cs): from layered to tunneled structure

Abstract

Attempts to prepare alkaline metal uranyl niobates of composition A{sub 1-x}UNbO{sub 6-x/2} by high-temperature solid-state reactions of A{sub 2}CO{sub 3}, U{sub 3}O{sub 8} and Nb{sub 2}O{sub 5} led to pure compounds for x=0 and A=Li (1), Na (2), K (3), Cs (4) and for x=0.5 and A=Rb (5), Cs (6). Single crystals were grown for 1, 3, 4, 5, 6 and for the mixed Na{sub 0.92}Cs{sub 0.08}UNbO{sub 6} (7) compound. Crystallographic data: 1, monoclinic, P2{sub 1}/c, a=10.3091(11), b=6.4414(10), c=7.5602(5)A, {beta}=100.65(1), Z=4, R{sub 1}=0.054 (wR{sub 2}=0.107); 3, 5 and 7 orthorhombic, Pnma, Z=8, with a=10.307(2), 10.272(4) and 10.432(3)A, b=7.588(1), 7.628(3) and 7.681(2)A, c=13.403(2), 13.451(5) and 13.853(4)A, R{sub 1}=0.023, 0.046 and 0.036 (wR{sub 2}=0.058, 0.0106 and 0.088) for 3, 5 and 7, respectively; 6, orthorhombic, Cmcm, Z=8, and a=13.952(3), b=10.607(2)A, c=7.748(2)A, R{sub 1}=0.044 (wR{sub 2}=0.117). The crystal structure of 1 is characterized by {sub {approx}}{sup 2}[UNbO{sub 6}]{sup -} layers of uranophane sheet anion topology parallel to the (100) plane. These layers are formed by the association by edge-sharing of {sub {approx}}{sup 1}[UO{sub 5}]{sup 4-} chains of edge-shared UO{sub 7} pentagonal bipyramids and {sub {approx}}{sup 1}[NbO{sub 4}]{sup 3-} chains of corner-shared NbO{sub 5} square pyramids alternating along the [010] direction. The Li{sup +}more » ions are located between two consecutive layers and hold them together; the Li{sup +} ions and two layers constitute a neutral ''sandwich'' {l_brace}(UNbO{sub 6}){sup -}-(Li){sub 2}{sup 2+}-(UNbO{sub 6}){sup -}{r_brace}. In this unusual structure, the neutral sandwiches are stacked one above another with no formal chemical bonds between the neutral sandwiches. The homeotypic compounds 3, 5, 6, 7 have open-framework structures built from the association by edge-sharing in two directions of parallel {sub {approx}}{sup 1}[UO{sub 5}]{sup 4-} chains of edge-shared UO{sub 7} pentagonal bipyramids and {sub {approx}}{sup 1}[Nb{sub 2}O{sub 8}]{sup 6-} ribbons of two edge-shared NbO{sub 6} octahedra further linked by corners. In 3, 5 and 7, the mono-dimensional large tunnels created in the [001] direction by this arrangement can be considered as the association by rectangular faces of two columns of triangular face-shared trigonal prisms of uranyl oxygens. In 3 and 7, all the trigonal prisms are occupied by the alkaline metal, in 5, they are half-occupied. In 6, the polyhedral arrangement is more symmetric and the tunnels created in the [010] direction are built of face-sharing cubes of uranyl oxygens totally occupied by the Cs atoms. This last compound well illustrates the structure-directing effect of the conterion.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1]
  1. Unite de Catalyse et de Chimie du Solide, UCCS UMR CNRS 8181, USTL, ENSCL-B.P. 90108, 59652 Villeneuve d'Ascq Cedex (France)
Publication Date:
OSTI Identifier:
20902469
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: 179; Journal Issue: 10; Other Information: DOI: 10.1016/j.jssc.2006.06.017; PII: S0022-4596(06)00359-8; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0022-4596
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANIONS; CESIUM COMPOUNDS; CHEMICAL BONDS; CRYSTALLOGRAPHY; LAYERS; LITHIUM COMPOUNDS; LITHIUM IONS; MONOCLINIC LATTICES; MONOCRYSTALS; NIOBATES; NIOBIUM OXIDES; ORTHORHOMBIC LATTICES; POTASSIUM COMPOUNDS; RUBIDIUM COMPOUNDS; SODIUM COMPOUNDS; URANIUM OXIDES U3O8; URANOPHANE

Citation Formats

Surble, S, Obbade, S, Saad, S, Yagoubi, S, Dion, C, and Abraham, F. The A{sub 1-x}UNbO{sub 6-x/2} compounds (x=0, A=Li, Na, K, Cs and x=0.5, A=Rb, Cs): from layered to tunneled structure. United States: N. p., 2006. Web. doi:10.1016/j.jssc.2006.06.017.
Surble, S, Obbade, S, Saad, S, Yagoubi, S, Dion, C, & Abraham, F. The A{sub 1-x}UNbO{sub 6-x/2} compounds (x=0, A=Li, Na, K, Cs and x=0.5, A=Rb, Cs): from layered to tunneled structure. United States. https://doi.org/10.1016/j.jssc.2006.06.017
Surble, S, Obbade, S, Saad, S, Yagoubi, S, Dion, C, and Abraham, F. Sun . "The A{sub 1-x}UNbO{sub 6-x/2} compounds (x=0, A=Li, Na, K, Cs and x=0.5, A=Rb, Cs): from layered to tunneled structure". United States. https://doi.org/10.1016/j.jssc.2006.06.017.
@article{osti_20902469,
title = {The A{sub 1-x}UNbO{sub 6-x/2} compounds (x=0, A=Li, Na, K, Cs and x=0.5, A=Rb, Cs): from layered to tunneled structure},
author = {Surble, S and Obbade, S and Saad, S and Yagoubi, S and Dion, C and Abraham, F},
abstractNote = {Attempts to prepare alkaline metal uranyl niobates of composition A{sub 1-x}UNbO{sub 6-x/2} by high-temperature solid-state reactions of A{sub 2}CO{sub 3}, U{sub 3}O{sub 8} and Nb{sub 2}O{sub 5} led to pure compounds for x=0 and A=Li (1), Na (2), K (3), Cs (4) and for x=0.5 and A=Rb (5), Cs (6). Single crystals were grown for 1, 3, 4, 5, 6 and for the mixed Na{sub 0.92}Cs{sub 0.08}UNbO{sub 6} (7) compound. Crystallographic data: 1, monoclinic, P2{sub 1}/c, a=10.3091(11), b=6.4414(10), c=7.5602(5)A, {beta}=100.65(1), Z=4, R{sub 1}=0.054 (wR{sub 2}=0.107); 3, 5 and 7 orthorhombic, Pnma, Z=8, with a=10.307(2), 10.272(4) and 10.432(3)A, b=7.588(1), 7.628(3) and 7.681(2)A, c=13.403(2), 13.451(5) and 13.853(4)A, R{sub 1}=0.023, 0.046 and 0.036 (wR{sub 2}=0.058, 0.0106 and 0.088) for 3, 5 and 7, respectively; 6, orthorhombic, Cmcm, Z=8, and a=13.952(3), b=10.607(2)A, c=7.748(2)A, R{sub 1}=0.044 (wR{sub 2}=0.117). The crystal structure of 1 is characterized by {sub {approx}}{sup 2}[UNbO{sub 6}]{sup -} layers of uranophane sheet anion topology parallel to the (100) plane. These layers are formed by the association by edge-sharing of {sub {approx}}{sup 1}[UO{sub 5}]{sup 4-} chains of edge-shared UO{sub 7} pentagonal bipyramids and {sub {approx}}{sup 1}[NbO{sub 4}]{sup 3-} chains of corner-shared NbO{sub 5} square pyramids alternating along the [010] direction. The Li{sup +} ions are located between two consecutive layers and hold them together; the Li{sup +} ions and two layers constitute a neutral ''sandwich'' {l_brace}(UNbO{sub 6}){sup -}-(Li){sub 2}{sup 2+}-(UNbO{sub 6}){sup -}{r_brace}. In this unusual structure, the neutral sandwiches are stacked one above another with no formal chemical bonds between the neutral sandwiches. The homeotypic compounds 3, 5, 6, 7 have open-framework structures built from the association by edge-sharing in two directions of parallel {sub {approx}}{sup 1}[UO{sub 5}]{sup 4-} chains of edge-shared UO{sub 7} pentagonal bipyramids and {sub {approx}}{sup 1}[Nb{sub 2}O{sub 8}]{sup 6-} ribbons of two edge-shared NbO{sub 6} octahedra further linked by corners. In 3, 5 and 7, the mono-dimensional large tunnels created in the [001] direction by this arrangement can be considered as the association by rectangular faces of two columns of triangular face-shared trigonal prisms of uranyl oxygens. In 3 and 7, all the trigonal prisms are occupied by the alkaline metal, in 5, they are half-occupied. In 6, the polyhedral arrangement is more symmetric and the tunnels created in the [010] direction are built of face-sharing cubes of uranyl oxygens totally occupied by the Cs atoms. This last compound well illustrates the structure-directing effect of the conterion.},
doi = {10.1016/j.jssc.2006.06.017},
url = {https://www.osti.gov/biblio/20902469}, journal = {Journal of Solid State Chemistry},
issn = {0022-4596},
number = 10,
volume = 179,
place = {United States},
year = {2006},
month = {10}
}