New alkaline earth-zirconium oxalates M{sub 2}Zr(C{sub 2}O{sub 4}){sub 4}.nH{sub 2}O (M=Ba, Sr, Ca) synthesis, crystal structure and thermal behavior

Journal Article · Mon Nov 01 04:00:00 EST 2004 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2004.06.053· OSTI ID:20658205

Chapelet-Arab, B ^[1]; Nowogrocki, G ^[1]; Abraham, F ^[1]; Grandjean, S ^[2]

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1. Laboratoire de Cristallochimie et Physicochimie du Solide, Universite des Sciences et Technologies de Lille, UMR CNRS 8012, ENSCL-USTL, B.P. 108, 59652 Villeneuve d'Ascq Cedex (France)
2. Laboratoire de Chimie des Actinides, CEA VALRHO/DRCP/SCPS, Ba-circumflex t 399 BP 17171 30208 Bagnols sur Ceze Cedex (France)

Three new alkaline earth-zirconium oxalates M{sub 2}Zr(C{sub 2}O{sub 4}){sub 4}.nH{sub 2}O have been synthesized by precipitation methods for M=Ba, Sr, Ca. For each compound the crystal structure was determined from single crystals obtained by controlled diffusion of M{sup 2+} and Zr{sup 4+} ions through silica gel containing oxalic acid. Ba{sub 2}Zr(C{sub 2}O{sub 4}){sub 4}.7H{sub 2}O, monoclinic, space group C2/c, a=9.830(2), b=29.019(6), c=9.178(2)A, {beta}=122.248(4){sup o}, V=2214.2(8)A3, Z=4, R=0.0427; Sr{sub 2}Zr(C{sub 2}O{sub 4}){sub 4}.11H{sub 2}O, tetragonal, space group I41/acd, a=16.139(4), c=18.247(6)A, V=4753(2)A3, Z=8, R=0.0403; Ca{sub 2}Zr(C{sub 2}O{sub 4}){sub 4}.5H{sub 2}O, orthorhombic, space group Pna2{sub 1}, a=8.4181(5), b=15.8885(8), c=15.8885(8)A, V=2125(2)A3, Z=4, R=0.0622. The structures of the three compounds consist of chains of edge-shared MO{sub 6}(H{sub 2}O){sub x} (x=2 or 3) polyhedra connected to ZrO{sub 8} polyhedra through oxalate groups. Depending on the arrangement of chains, the ZrO{sub 8} polyhedron geometry (dodecahedron or square antiprism) and the connectivity, two types of three-dimensional frameworks are obtained. For the smallest M{sup 2+} cations (Sr{sup 2+}, Ca{sup 2+}), large tunnels are obtained, running down the c direction of the unit cell, which can accommodate zeolitic water molecules. For the largest Ba{sup 2+} cation, the second framework is formed and is closely related to that of Pb{sub 2}Zr(C{sub 2}O{sub 4}){sub 4}.nH{sub 2}O. The decomposition at 800{sup o}C into strontium carbonate, barium carbonate or calcium oxide and MZrO{sub 3} (M=Sr, Ba, Ca) perovskite is reported from thermal analyses studies and high temperature X-ray powder diffraction.

• OSTI ID: 20658205
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 11 Vol. 177; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
BARIUM CARBONATES
BARIUM COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM IONS
CALCIUM OXIDES
CATIONS
MONOCLINIC LATTICES
ORTHORHOMBIC LATTICES
OXALATES
OXALIC ACID
SPACE GROUPS
STRONTIUM CARBONATES
STRONTIUM COMPOUNDS
STRONTIUM IONS
TEMPERATURE RANGE 1000-4000 K
TETRAGONAL LATTICES
THERMAL ANALYSIS
X-RAY DIFFRACTION
ZIRCONIUM COMPOUNDS
ZIRCONIUM IONS