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1.
On the Structure of Ba3SmRu2O9, Ba3SmIrRuO9, and Ba2InIrO6 The compounds Ba3SmRu2O9, Ba3SmIrRuO9, and Ba2InIrO6 have a hexagonal BaTiO3 structure (sequence (hcc)2) with an ordered cationic distribution. The 6 L stacking polytypes Ba3BM2O9 show an 1:2 order (M2O9 double octahedra and BO6 single groups) and crystallize in the space group P63/mmc. The refined, intensity related R′ values are 6.9% (Ba3SmRu2O9) and 6.5% (Ba3SmIrRuO9). The 1:1 ordered Ba2InIrO6, with InIrO9 double groups and InO6?, IrO6-single octahedra, belongs to the space group P3 m1; the refined R′ is 7,3%. 相似文献
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《Journal of solid state chemistry》2004,177(4-5):1493-1500
Single crystals of Ba3LiIr2O9, Ba3NaIr2O9, and Ba3.44K1.56Ir2O10 were grown from hydroxide fluxes. Ba3LiIr2O9 and Ba3NaIr2O9 form in the 6H–BaTiO3 or triple perovskite structure, which is derived from the hexagonal and cubic stacking of [AO3] layers. The structure contains face-sharing Ir2O9 octahedra pairs, which are connected via corner shared LiO6 (NaO6) octahedra. Both compounds crystallize in the space group P63/mmc, Z=2, with a=5.7804(4) and c=14.302(1) and a=5.866(4) and c=14.596(1) for the Li and Na member, respectively. The structure of Ba3.44K1.56Ir2O10 is derived from the stacking of [AO3] and mixed [A2O] layers, and is an n=3 member of the [AnMn−1O3n][A2O] family of hexagonal perovskite related oxides. The structure of Ba3.44K1.56Ir2O10 consists of (Ba3Ir2O9) slabs separated by [(Ba,K)2O] layers and is isostructural with Ba5Ru2O10. The (Ba3Ir2O9) slabs contain isolated, face-sharing Ir2O9 octahedra pairs. The compound crystallizes in the space group P63/mmc, Z=2, with a=5.91330(1) Å and c=18.1792(7) Å. The magnetic moments determined from the temperature dependence of the magnetic susceptibility are low for all three oxides, which is thought to be due to a combination of spin–orbit coupling and strong exchange interactions within the iridium octahedra pairs. 相似文献
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The crystal structure of Ba3W2O9 contains isolated W2O6?9 groups. These are reported to luminesce efficiently. This shows that clusters of tungstate octahedra emit more efficiently than the isolated species. 相似文献
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Hans-Conrad zur Loye Seung-Joo Kim Rene Macquart Mark D. Smith Yongjae Lee Tom Vogt 《Solid State Sciences》2009,11(3):608-613
Single crystal X-ray and synchrotron X-ray powder diffraction have been used to probe the structure of Ba3NaIr2O9 from 300 K down to 20 K. Ba3NaIr2O9 is found to undergo a structural transition from hexagonal symmetry, P63/mmc, at ambient temperature to monoclinic symmetry, C2/c, at low temperature. The evolution of the unit cell volume upon cooling is indicative of a higher order structural transition, and the symmetry breaking becomes apparent as the temperature is decreased. The low temperature monoclinic structure of Ba3NaIr2O9 contains strongly distorted [NaO6] and [IrO6] octahedra in comparison to the room temperature hexagonal structure. 相似文献
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The Structures of the Hexagonal Elpasolite-Type Compounds Ba3NiSb2O9 and Ba3CuSb2O9 The results of an X-ray single crystal study of the hexagonal elpasolite Ba(NiSb2)(6)O9 are given. (Space group: C; a = b = 5.837 Å, c = 14.392 Å; Z = 2). The structure can be described by close-packed BaO3 layers alternating in the sequence c c h c c h … (hex. BaTiO3 type). Groups of two octahedra with common faces are connected by SbO6 octahedra via common corners. They are occupied alternately by Ni and Sb. The final reliability index was R = 3.0%. The Cu2+-compound is of the same structural type. The ligand field and EPR spectra are discussed in comparison with related Ni2+ and Cu2+ compounds. 相似文献
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P. Kuhl 《无机化学与普通化学杂志》1978,442(1):280-288
Crystal Structure of the Hexagonal Compounds BaII3MeIISbv2O9. II. Ba3CuSb2O9 The crystal structure of the compound Ba3CuSb2O9 was determined from single crystal X-ray diffraction data and refined down to R = 0.03. Ba3CuSb2O9 crystallizes in the hexagonal space group P63mc (C) with a = b = 5.809 Å, C = 14.321 Å and Z = 2. The structure can be described by close–packed BaO3 layers in the sequence cchcchcch…?(hex. BaTiO3 type). Groups of two octahedra with common faces are connected by SbO6 octahedra via common corners. They are occupied alternately by Cu and Sb. In agreement with the EPR spectra the CuO6-octahedra present no static Jahn-Teller distortion at room temperature. However the thermal ellipsoids of the oxygen atoms indicate the presence of adynamic Jahn-Teller-effect. 相似文献
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Matthew Mann Joseph Kolis 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(4):i17-i19
Dibarium dititanium difluoride dioxide heptaoxidodisilicate, Ba2Ti2Si2O9F2, is a new edge‐sharing titanate with a unique titanium silicate framework. All atoms in the structure are in general positions. Titanium oxyfluoride octahedra combine with silicon tetrahedra to form a double stacked chain, which is the base unit of the layered framework. The Ba atoms lie in channels that extend along the a axis. 相似文献
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Ba3Lu4O9: Synthesis and Crystal Structure Determination Single crystals of Ba3Lu4O9 were prepared by high temperature reactions (CO2-Lasertechnique). The single crystal X-ray work leads to a rhombohedral symmetry with a = 8.96 Å and α = 39.42° (space group C—R3). Characteristic features of this crystal structure are shown and discussed. 相似文献
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A. Thrierr-sorel D. Tacquenet M. H. Simonot-grange 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):73-78
Abstract Ba3(P3O9)26H2O and Ca3(P3O9)26H2O have mobile H2O's which, under a dynamic vacuum of about 0.133 Pa, leave the lattice without disrupting it. Under water-vapor pressure, dehydration is accompanied by hydrolysis of P3O9 3- rings. The final product of dehydration is the β polyphosphate. 相似文献
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New Structure Type of the Two Oxohalogenoferrites: Ba3Fe2O5Cl2 and Ba3Fe2O5Br2 The hitherto unknown compounds Ba3Fe2O5Cl2 (A) and Ba3Fe2O5Br2 (B) are pre-pared and examined by single crystal techniques. (A) and (B) crystallizes in the cubic space group I21 3-T5; (A) a = 9.9705(3) and (B) a = 10.0039(8) Å, Z = 4. The new structure consists of 10 corner-shared tetrahedra which are connected to a two-dimensional ring system. The differences to the previously investigated compound Sr3Fe2O5Cl2 are discussed. 相似文献
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The New Layer‐Silicates Ba3Si6O9N4 and Eu3Si6O9N4 The new oxonitridosilicate Ba3Si6O9N4 has been synthesized in a radiofrequency furnace starting from BaCO3, amorphous SiO2 and Si3N4. The reaction temperature was at about 1370 °C. The structure of the colorless compound has been determined by single‐crystal X‐ray diffraction analysis (Ba3Si6O9N4, space group P3 (no. 143), a = 724.9(1) pm, c = 678.4(2) pm, V = 308.69(9)· 106 pm3, Z = 1, R1 = 0.0309, 1312 independent reflections, 68 refined parameters). The compound is built up of corner sharing SiO2N2 tetrahedra forming corrugated layers between which the Ba2+ ions are located. Substitution of barium by europium leads to the isotypic compound Eu3Si6O9N4. Because no single‐crystals could be obtained, a Rietveld refinement of the powder diffractogram was conducted for the structure refinement (Eu3Si6O9N4, space group P3 (no. 143), a = 711.49(1) pm, c = 656.64(2) pm, V = 287.866(8) ·106 pm3, Rp = 0.0379, RF2 = 0.0638). The 29Si MAS‐NMR spectrum of Ba3Si6O9N4 shows two resonances at ?64.1 and ?66.0 ppm confirming two different crystallographic Si sites. 相似文献
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On Ruthenium perovskites of type Ba2BRuO6 and Ba3BRu2O9 with B = Indium, Rhodium The black perovskites Ba2InRu5+O6 and Ba3InRu2O9 (mean oxydation state of ruthenium: +4.5) adopt the hexagonal BaTiO3 structure and form a continuous series of mixed crystals. According to the intensity calculations and analysis of the vibrational spectroscopic data an ordered distribution between indium and ruthenium is present: 1:1 order in Ba2InRuO6 (space group P3 m1 ? D; R′ = 5.3%); 1:2 order in Ba3InRu2O9 (space group P63/mmc ? D; R′ = 4.6%). The corresponding black Rh compounds, Ba2RhRuO6 and Ba3RhRu2O9, crystallize in the rhombohedral 9 L type of BaRuO3. 相似文献
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About the Crystal Structure of Ba3In2O6 Single crystals of Ba3In2O6 could be prepared by recrystallization of a flux and by solid state reaction in closed platinium tubes, respectively. Ba3In2O6 crystallizes with tetragonal symmetry (space group 14/mmm, a = 4.1868; c = 21.7041 Å, Z = 2). Single crystal X-ray work lead to a crystal structure like La2-xSr1+xCu2O6-δ therefor Ba3In2O6 is a modified member of the Sr3Ti2O7-Type. The coordinations of Ba2+ and In3+ are described and the relations to the Sr3Ti2O7-type are discussed. 相似文献
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Michael Boss Frank Pickhard Markus Zumdick Caroline Rhr 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(5):503-504
The antimonide oxide Ba3Sb2O consists of discrete [Sb2]4? and O2? anions, and crystallizes with a new structure type. The Sb—Sb distances are comparable to those known from electron‐precise zintl phases and the tetrahedral coordination of the O2? anion is also observed in some other Ba‐rich metallide oxides. 相似文献
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In this paper we investigated the phase formation and structural ordering in spin-coated Ba3ZnNb2O9 perovskite films using confocal Raman microscopy. The films were deposited through polyester resins obtained from a polymeric precursor. Initially, the films were characterized by X-ray diffraction and atomic force microscopy. Raman spectroscopy confirmed the crystalline structure of the main phase, as well as its partially disordered feature. Raman mappings were employed to probe the secondary phase distribution in the films, and to determine the calcining time-dependent film thicknesses. 相似文献
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采用以尿素水解为基础的水热合成法制备了La和Mn取代的六铝酸盐催化剂(Ba1-xLaxMn3Al9O19-α).在Mn含量达到阈值时,研究了不同量的La取代Ba对Ba1-xLaxMn3Al9O19-α的相组成、结构、热稳定性及甲烷催化燃烧活性的影响.当x≥0.4时,水热合成过程中生成的La2(CO3)3在530-580℃分解,800-900℃时与-γAl2O3反应生成LaAlO3钙钛矿相,可抑制由BaCO3分解而生成的Ba2+的固相扩散,从而阻止了BaAl2O4尖晶石相的生成,使Ba2+在固相中保持较高的分散性,促进了六铝酸盐(-βAl2O3)相的形成.当x<0.4时,BaAl2O4尖晶石相的存在引起催化剂比表面积和催化燃烧活性的降低.La3+取代Ba2+后,六铝酸盐结构发生一定程度的扭变.这种扭变越大,所形成的六铝酸盐催化剂的热稳定性越差.Ba1-xLaxMn3Al9O19-α催化剂的甲烷催化燃烧活性随x的增大而增加,x=0.8时催化剂的活性最佳. 相似文献