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Hydrothermal Conditions (hydrothermal + condition)
Selected AbstractsCrystalline Transition from H2Ti3O7 Nanotubes to Anatase Nanocrystallines Under Low-Temperature Hydrothermal ConditionsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2006Ning Wang In this paper, we first reported the crystalline transition from H2Ti3O7 nanotubes to anatase TiO2 nanocrystallines under low-temperature hydrothermal conditions (,140°C). A newly proposed mechanism for the crystalline transition from H2Ti3O7 nanotubes to anatase TiO2 nanocrystallines under low-temperature conditions is discussed in detail, which is supported by X-ray diffraction, high-resolution transmission electronic microscope, selected-area electron diffraction, and crystal structure models. [source] Decomposition of a Lignin Model Compound under Hydrothermal ConditionsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 8 2007Wahyudiono Abstract Lignin, which is the second most abundant polymeric aromatic organic substance in wood biomass after cellulose, and contains many oxygen-based functional groups, has been proposed as an alternative source of chemical compounds. Guaiacol, a model compound for lignin, was reacted in supercritical water using a batch-type reactor at temperatures of 653,673,K and various pressures under an argon atmosphere. The effects of temperature and reaction time at the same pressure were combined into a single severity parameter that was used to monitor the decomposition of guaiacol to its derived compounds. The main products in aqueous solution were catechol, phenol, and o -cresol. The amounts present approached 40.73,wt,%, 14.18,wt,%, and 4.45,wt,%, respectively. With an increase in the reaction time at the same conditions, the amount of guaiacol decreased and the quantity of derived compounds of guaiacol increased. Based on the experimental results, a reaction mechanism for the decomposition of guaiacol was proposed. The process investigated in this study may form the basis for an efficient method of wood biomass decomposition. [source] Combination of Lacunary Polyoxometalates and High-Nuclear Transition Metal Clusters under Hydrothermal Conditions.CHEMINFORM, Issue 33 2007Part 3. Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Critical Role of Water Content in the Formation and Reactivity of Uranium, Neptunium, and Plutonium Iodates under Hydrothermal Conditions: Implications for the Oxidative Dissolution of Spent Nuclear Fuel.CHEMINFORM, Issue 30 2007Travis H. Bray Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Hydrolysis of Acetals in Water under Hydrothermal Conditions.CHEMINFORM, Issue 10 2004Kimihiko Sato Abstract For Abstract see ChemInform Abstract in Full Text. [source] Self-Assembly of 1D to 3D Cadmium Complexes: Structural Characterization and PropertiesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 15 2005Xing Li Abstract Self-assembly reactions of 5-sulfoisophthalic monosodium salt (NaH2sipa), Cd(NO3)2·4H2O and 2,2'-bipyridine (or 4,4'-bipyridine) under hydrothermal condition give rise to four polymeric complexes, namely {[Cd3(sipa)2(2,2'-bpy)4(H2O)2]·6H2O}n (1), {[Cd(sipa)(H-4,4'-bpy)(H2O)]·2H2O}n (2); {[Cd2(sipa)(4,4'-bpy)3(H2O)3]·[Cd(sipa)(4,4'-bpy)(H2O)]·8H2O}n (3),and {[Cd3(sipa)2(4,4'-bpy)4(H2O)2]·3H2O}n (4), respectively. X-ray diffraction analyses reveal that complex 1 possesses a 1D rail-like chain structure, 2 is a 1D double chain, 3 has a 2D network consisting of an independent [Cd2(sipa)(4,4'-bpy)3(H2O)3]nn+ cationic layer and a [Cd(sipa)(4,4'-bpy)(H2O)]nn, anionic layer, and 4 is a novel 3D self-penetrating network constructed from two mixed bridging ligands. Thermogravimetric analyses (TGA) and fluorescent measurements of complexes 1,4 have also been performed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Performance under thermal and hydrothermal condition of amorphous silica membrane prepared by chemical vapor depositionAICHE JOURNAL, Issue 8 2009Kazuki Akamatsu First page of article [source] Two novel benzenedicarboxylate-metal complexes: synthesis, crystal structures and fluorescent propertiesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2007Yi-Shan Song Abstract Two novel benzenedicarboxylate,metal complexes, [Sm(nphth)(Hnphth)(H2O)3,H2O]2 and [Zn(nphth)(bipy)(H2O) ,H2O]2 (2) (H2nphth = 3-nitrophthalic acid, bipy = 2,2,-bipyridine), have been synthesized under hydrothermal condition and characterized by single-crystal X-ray diffraction. Both complex 1 and 2 exhibit a dimeric structure, and nphth ligand shows different coordination mode in the f-block and d-block complexes. The fluorescent properties of two complexes are investigated; the results reveal that the two complexes show different kinds of fluorescence. Copyright © 2007 John Wiley & Sons, Ltd. [source] A new piezoelectric single crystal obtained by Ge doping in the SiO2 structureCRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2009M. Miclau Abstract The interest of Si1,xGexO2 single crystals with alpha-quartz structure is connected to improvement of electromechanical coefficients and rise of , , , phase transition of quartz one. Growth of an ,-SixGe1,xO2 crystal was realized by a hydrothermal method of temperature gradient in autoclaves, made from Cr,Ni alloys. Nutrient material was prepared from synthetic quartz as crashed rods and placed in the bottom of autoclaves. There was loaded GeO2 powder additive in proportions to quartz nutrient. Single crystals were investigated by electron microprobe analysis, X-ray diffraction and atomic force microscopy. The most important result, which was obtained during the investigations, is an experimental proof of growth of ,-SixGe1,xO2 single crystals under the hydrothermal conditions. The present results thus open the possibility to tune the piezoelectric properties of these materials by varying the chemical composition. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis, characterization of an unusual crystalline material with tartrateCRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2008Yongbing Gu Abstract An exploration of the cobalt-tartrate system under hydrothermal conditions, has led to the isolation of crystalline framework {Co2(H2tar)2]·2H2O}n (1) (H2tar = tartrate dianion). Single-crystal X-ray analyses reveal that it crystallizes in the orthorhombic space group P21212. a = 11.0924(11) Å, b = 7.8517(8) Å, c = 9.0171(9) Å, , = 90°. A dinuclear CoII unit is formed via two different coordinated tartrate molecules. Further these units are united together through two bridging carboxylate groups of hexa-coordinated H2tar ligands to form a 2D grid layer, which exhibits a typical (6,3) topological network. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis, characterization and crystal structure of a porous crystalline materialCRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2008Chun-Sheng Zhou Abstract An exploration of the nickel-malate-bpp system under hydrothermal conditions, has led to the isolation of a novel framework {[Ni(Hmal)(bpp)]·5H2O}n (1) (Hmal = malate dianion, bpp = 1,3-bi(4-pyridyl)propane). Single-crystal X-ray analyses reveal that it crystallizes in the orthorhombic space group Pccn. a = 21.141(3) Å, b = 10.4028(16) Å, c = 19.250(3) Å. The Ni(II) ions are linked into an extended helical chain via Hmal molecules. Further these chains are united together through the bridging bpp to form a 3D porous framework, which exhibits an unusual NbO-type topological network. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis, characterization and crystal structure of a novel 2D Ni(II) complex with malateCRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2008Weiping Wu Abstract An exploration of the nickel- malate-bpa system under hydrothermal conditions, has led to the isolation of a novel framework {[Ni(Hmal)(bpa)]·2.5H2O}n (1) (Hmal = malate dianion, bpa = 1,2-bi(4-pyridyl)ethane). Single-crystal X-ray analyses reveal that it crystallizes in the orthorhombic space group Fdd2. a = 21.9944(13) Å, b =33.3369(19) Å, c = 10.3969(5) Å, , = 90°. The NiII ions are linked into an extended helical chain via Hmal molecules. Further these chains are united together through the bridging bpa to form a 2D grid layer, which exhibits a typical (6,3) topological network. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Particle size of powders under hydrothermal conditionsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2003Wen-Jun Li Abstract Various non-oxide (CuI, AgI, AgCl, PbS, CuS and ZnS) and oxide (ZnO, TiO2, SnO2, CeO2 and ZrO2) powders were prepared under hydrothermal conditions to investigate the effects of temperature, pH and precursors on the particle size of powders. It was found that the particle sizes of PbS, CuS and ZnS powders were much smaller than that of CuI, AgI and AgCl powders prepared under the same conditions. The particle sizes of TiO2, SnO2, CeO2 and ZrO2 powders are much smaller than that of ZnO powders prepared under the same conditions. It is concluded that the solution conditions have a certain effect on the particle size of powders under the hydrothermal conditions. The particle size of powders increased with the rising of temperature. Additional factors affecting the particle size were uncovered through studying the nucleation mechanism. The particle size was mainly related to the Madelung constant and the electric charge number of ions. Powders with smaller particle size resulted from systems that possessed the larger Madelung constant and ionic charge number. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Novel (3,4)- and (4,5)-Connected Lanthanide Metal,Organic FrameworksEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 1 2008Xian-Wen Wang Abstract The three-dimensional lanthanide noninterpenetrating metal,organic frameworks formulated as [Ln(3,5-pdc)(C2O4)0.5(H2O)2]·H2O (Ln = LuIII, GdIII, TmIII and YbIII for complex 1,4, respectively; 3,5-pdc = 3,5-pyridinedicarboxylate) were synthesized by hydrothermal reactions of 3,5-H2pdc with lanthanide oxide and perchloric acid. Compound 1 shows (3,4)-connected (4.82)(4.85) dmc-type topological network, and complexes 2,4 display the novel (4,5)-connected (44.6.8)(44.62.84) xww-type topology. The lanthanide-mediated transformation of CO2 to oxalate under hydrothermal conditions was observed. The fluorescence properties of complexes 1,4 were investigated. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Square-Planar Noble Metal Iodate [M(IO3)4]n, (M = PdII, AuIII; n = 2, 1) Anions and Their Ability to Form Polar and Centrosymmetric ArchitecturesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 5 2007Jie Ling Abstract K+ salts of the square-planar noble metal iodate [M(IO3)4]n, (M = PdII, AuIII; n = 2, 1) anions have been prepared under mild hydrothermal conditions, and the structures elucidated to demonstrate that while both are highly polar anions, polar and centrosymmetric extended architectures can form using these building units. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Nickel-Organic Coordination Layers with Different Directional CavitiesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2006Youfu Zhou Abstract The two new metal-organic coordination frameworks [Ni2(pydc)2(4,4,-bpy)(H2O)4]n·0.5n(4,4,-bpy)2H2O (1) and [Ni2(pydc)2(2,2,-bpy)2(H2O)2]n·2nH2O (2) (H2pydc = pyridine-3,4-dicarboxylic acid; bpy = bipyridine) have been synthesised under hydrothermal conditions and characterised by single-crystal X-ray diffraction analysis. The structure of 1 contains parallel rectangular channels that accommodate large 4,4,-bpy guests while that of 2 contains vertical channels coordinated to 2,2,-bpy ligands. Their magnetic analyses show that they exhibit different magnetic interactions. The red shifts of the peak in their emission spectra relative to those of the the free ligands could be attributable to the metal,ligand coordination. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Novel Metallosupramolecular Networks Constructed from CuII, NiII, and CdII with Mixed Ligands: Crystal Structures, Fluorescence, and MagnetismEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 6 2006Miao Du Abstract Reactions of mixed ligands succinic acid (H2suc) and bent dipyridines, such as 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) and its 4- N -donor analog (4-bpo), with inorganic CuII, NiII, and CdII salts yield three new metal-organic coordination frameworks {[Cu(suc)(3-bpo)(H2O)2]·(H2O)1.75}n (1), {[Ni(suc)(4-bpo)(H2O)2]·(H2O)5}n (3), and {[Cd2(suc)2(3-bpo)2(H2O)2]·(H2O)6.75}n (4), in which the metal centers are linked by bridging ligands 3-bpo/4-bpo and suc2, along two directions to form 2D infinite networks. The corrugated 2D nets of 1 and 4, obtained under hydrothermal conditions, align in an interdigitated manner with the presence of significant aromatic-stacking interactions to result in similar 3D architectures. The 2D sheets in 3 are extended by interlayer hydrogen bonds to afford a 3D structure. However, when succinic acid is replaced by fumaric acid (H2fum) in the reaction with 3-bpo and CuII salt, a metallacyclophane [Cu(Hfum)2(3-bpo)(H2O)]2·(3-bpo)2·(H2O)6 (2) is generated. The binuclear coordinated motifs are hydrogen-bonded to the lattice water chains to furnish a unique 3D channel-like framework, in which the guest 3-bpo molecules are accommodated. The thermal stabilities of these new materials were investigated by thermogravimetric analysis (TGA) of mass loss. The magnetic coupling in complexes 1,3 is antiferromagnetic and very small, which is as expected considering the long organic bridges between the paramagnetic centers. The solid-state luminescence properties of 4 reveal an intense fluorescence emission at 378 nm. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Novel Phosphovanadate Layered Structure Assembled from a Tetrametallic Cubane-Like VV ClusterEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 15 2004Fa-Nian Shi Abstract A novel phosphovanadate layered structure intercalated by 4,4,-bipyridinium cations, (C10H10N2)[(VO2)4(PO4)2], was synthesised under hydrothermal conditions and its crystal structure determined using single-crystal X-ray diffraction. The anionic [(VO2)4(PO4)2]n2n, perforated layers are strongly hydrogen bonded to the interlayer 4,4,-bipyridinium cations and are assembled by an unprecedented secondary tetrametallic VV building unit constructed from a distorted cubane-like {V4O4} cluster. The compound was further characterised by IR, Raman, 1H, 1H- 13C, 31P and 51V MAS NMR spectroscopy, and by thermal and elemental analysis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Self-Assembly of Organodiphosphonate, Polyoxomolybdate and Diphenanthrolinecobalt(II) into Two Clusters and One Linear PolymerEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 9 2003Rui-Biao Fu Abstract [{Co(1,10-phen)2}2{(Mo4O12)(O3PCH2CH2PO3)}·(H2O)] (1), [{Co(1,10-phen)2}2{(Mo4O12)(O3PCH2CH2CH2PO3)}·(1.5H2O)] (2) and [{Co(1,10-phen)2(H2O)2}{Co(1,10-phen)2(H2O)}{(Mo5O15)(O3PCH2CH2CH2CH2PO3)}·(6H2O)] (3) were synthesized by self-assembly of H2O3P(CH2)nPO3H2 (n = 2,4), polyoxomolybdate and [Co(1,10-phen)2]2+ (1,10-phen = 1,10-phenanthroline) under hydrothermal conditions. Compounds 1 and 2 are novel heterometallic hexanuclear clusters, while compound 3 is a new linear polymer. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Template Synthesis of Aligned Carbon Nanotube Arrays using Glucose as a Carbon Source: Pt Decoration of Inner and Outer Nanotube Surfaces for Fuel-Cell Catalysts,ADVANCED FUNCTIONAL MATERIALS, Issue 6 2008Zhenhai Wen A facile method is developed to synthesize aligned arrays of open-ended carbon nanotubes (CNTs) via in situ glucose polymerization in the inner pores of anodic aluminum oxide templates under hydrothermal conditions, followed by carbonization at high temperature. Pt nanoparticles are decorated on the surfaces of the as-prepared CNTs using the incipient wet method based on the use of NaBH4 as a reductant. Characterization of the resulting structures by transmission electron microscopy and field-emission scanning electron microscopy demonstrates that the Pt nanoparticles are anchored on both the inner and outer walls of CNTs, thus giving rise to a shell,core,shell-like nanotube composite. The electrocatalytic properties of the Pt,CNT,Pt electrodes are investigated for methanol oxidation by cyclic voltammetry and chronoamperometric measurements. It is found that the hybrid electrodes show superior catalytic performance compared to commercial carbon-black-supported Pt. The increased catalytic efficiency of Pt might be a result of the unique morphology of these structures. [source] Hydrothermal Syntheses of Gold Nanocrystals: From Icosahedral to Its Truncated Form,ADVANCED FUNCTIONAL MATERIALS, Issue 2 2008J. Xu Abstract We have successfully controlled the shape of gold nanocrystals through a simple and low-cost hydrothermal method based on a modified polyol process. Well-defined gold nanocrystals of icosahedral shape were synthesized in high yields by the rapid reduction of gold precursors with ethylene glycol (EG) in the presence of poly(vinyl pyrrolidone) (PVP) under hydrothermal conditions for 1 h. Truncated icosahedra (football-shaped) have been prepared for the first time by prolonging the reaction time to 4 h. Both nanocrystal shapes were obtained quantitatively. Addition of citric acid inhibits the shape-change process (from icosahedron to truncated icosahedron) by blocking oxidative etching, while addition of Fe(III) facilitates the shape-change process by enhancing oxidative etching. We propose that growth of truncated icosahedra can be induced and maintained through interplay of the following processes: generation of multiple twinned seeds, shape- and size-focusing by Ostwald ripening, and oxidative etching and preferential growth on the {100} face. [source] An Aqueous Emulsion Route to Synthesize Mesoporous Carbon Vesicles and Their NanocompositesADVANCED MATERIALS, Issue 7 2010Dong Gu Onionlike mesoporous carbon and carbon,silica nanocomposites with multilayer vesicle structures can be synthesized by an organic,inorganic co-assembly method under hydrothermal conditions in an aqueous emulsion solution (see figure). The nanocomposite vesicles have ordered lamellar mesostructures with about 3,9 layers and carbon pillars are located between the neighboring shells. [source] Hydrothermal modification of natural zeolites to improve uptake of ammonium ionsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2005Yujiro Watanabe Abstract The modification of natural zeolites was carried out under hydrothermal conditions to improve the effectiveness of the uptake of ammonium ions. Natural zeolites originating in Japan, such as mordenite and clinoptilolite with quartz, feldspar and a trace of layered silicate, were treated with 0.1, 0.3, 1.0 and 3.0 M NaOH solutions at temperatures from 25 to 150 °C under autogenous pressure for 7 days. After the hydrothermal treatment, the transformation of the zeolites to phillipsite, hydroxyl-sodalite and analcime was observed, depending on the temperature and NaOH concentration. The amounts of ammonium ions taken up into the hydrothermally-treated zeolites were compared with those of the starting materials. The treated products, containing mainly phillipsite, took up twice the amount of ammonium ions as the starting materials. The maximum uptake of ammonium ions was 1.92 mmol g,1. The number of ammonium ions taken up into phillipsite was equal to the number of Na+ ions released from phillipsite. These results indicate that the uptake of ammonium ions proceeds by an ion-exchange mechanism with Na+ ions. Copyright © 2005 Society of Chemical Industry [source] Synthesis of ZSM-5 from diatomite: a case of zeolite synthesis from a natural materialJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2004Vilma Sanhueza Abstract A highly crystalline ZSM-5 product was obtained from diatomite, a natural raw material, both with and without the presence of diethanolamine. The synthesis process took 40 h, and was carried out under hydrothermal conditions, at autogenic pressure, and at a temperature of 180 °C. The resulting crystals were identified as ZSM-5 by X-ray diffraction and characterized by scanning electron microscopy, infrared spectroscopy, thermal gravimetry and differential thermal analysis. Copyright © 2004 Society of Chemical Industry [source] Synthesis of mordenite from diatomite: a case of zeolite synthesis from natural materialJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2003Vilma Sanhueza Abstract A high mordenite product was obtained from a natural raw material, diatomite, either with or without the presence of diethanolamine. The synthesis process took 2 days, and was carried out under hydrothermal conditions, at autogenic pressure, and at a temperature of 180 °C. The resulting crystals were identified as mordenite by X-ray diffraction and characterized by scanning electron microscopy, and differential thermal and gravimetric analyses. Copyright © 2003 Society of Chemical Industry [source] Crystalline Transition from H2Ti3O7 Nanotubes to Anatase Nanocrystallines Under Low-Temperature Hydrothermal ConditionsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2006Ning Wang In this paper, we first reported the crystalline transition from H2Ti3O7 nanotubes to anatase TiO2 nanocrystallines under low-temperature hydrothermal conditions (,140°C). A newly proposed mechanism for the crystalline transition from H2Ti3O7 nanotubes to anatase TiO2 nanocrystallines under low-temperature conditions is discussed in detail, which is supported by X-ray diffraction, high-resolution transmission electronic microscope, selected-area electron diffraction, and crystal structure models. [source] Formation of Novel ZSM-5/Porous Mullite Composite from Sintered Kaolin Honeycomb by Hydrothermal ReactionJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2000Hiroaki Katsuki The formation and properties of continuous ZSM-5 film on a porous mullite honeycomb have been investigated. The porous mullite honeycomb coated with ZSM-5 film provides a novel microporous (0.5 nm in diameter),macroporous (0.5,0.6 ,m in diameter) composite. Amorphous silica-glass in the kaolin honeycomb sintered at 1650°C is used as a source for ZSM-5 formation. The honeycomb is hydrothermally treated in NaOH, tetrapropylammonium bromide, and water to prepare a novel honeycomb,zeolite composite by in situ crystallization of ZSM-5 film. This paper describes the effects of hydrothermal conditions,such as reaction temperature, time, and concentration of NaOH solution,on the formation of ZSM-5 film on the honeycomb, and on the mechanical strength and porous properties of the honeycomb composite. [source] The solid solution (Fe0.81Al0.19)(H2PO4)3 with a strong hydrogen bondACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2010Nadia Belfguira Single crystals of the solid solution iron aluminium tris(dihydrogenphosphate), (Fe0.81Al0.19)(H2PO4)3, have been prepared under hydrothermal conditions. The compound is a new monoclinic variety (,-form) of iron aluminium phosphate (Fe,Al)(H2PO4)3. The structure is based on a two-dimensional framework of distorted corner-sharing MO6 (M = Fe, Al) polyhedra sharing corners with PO4 tetrahedra. Strong hydrogen bonds between the OH groups of the H2PO4 tetrahedra and the O atoms help to consolidate the crystal structure. [source] 12-Membered borophosphate rings in KNi5[P6B6O23(OH)13]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009Olga V. Yakubovich The title compound, potassium pentanickel hexaborophosphate tridecahydroxide, was synthesized under hydrothermal conditions from the NiCl2,K3PO4,B2O3,K2CO3,H2O system. The crystal structure was determined using single-crystal X-ray diffraction at 100,K. The KNi5[P6B6O23(OH)13] phase is cubic. For the three crystallographically distinct Ni centers, two occupy sites with 3 symmetry, while the third Ni and the K atom are located on sites. The structure is built from alternating borate and phosphate tetrahedra forming 12-membered puckered rings with K+ ions at the centers. These rings are arranged as in cubic dense sphere packing. A novel feature of the new crystal structure is the presence of linear trimers of face-sharing [NiO6] octahedra occupying the octahedral interstices of this sphere packing, and of single [NiO6] octahedra in the tetrahedral interstices. All oxygen corners of the Ni octahedra are linked to phosphate or borate tetrahedra of the 12-membered rings to form a mixed anionic framework. [source] Poly[bis(,3 -5,-carboxy-2,2,-bipyridine-5-carboxylato-,4O:N,N,:O,)lead(II)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009Cheng-Zhi Xie The title compound, [Pb(C12H7N2O4)2]n, obtained by reaction of Pb(NO3)2 and 2,2,-bipyridine-5,5,-dicarboxylic acid (H2bptc) under hydrothermal conditions, has a structure in which the unique PbII cation sits on a twofold axis and is octa-coordinated by four O-atom donors from four Hbptc, ligands and four N-atom donors from two Hbptc, ligands in a distorted dodecahedral geometry. With each PbII cation connected to six Hbptc, ligands and each Hbptc, ligand bridging three PbII cations, a three-dimensional polymeric structure is formed. From a topological point of view, the three-dimensional net is binodal, with six-connected (the PbII cation) and three-connected (the Hbptc, ligand) nodes, resulting in a distorted rutile (42.8)2(4489122) topology. [source] | |||||||||||||||||||||||||