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Diffraction Study (diffraction + study)
Kinds of Diffraction Study Selected AbstractsAn Energy Dispersive X-ray Diffraction Study of Dioxouranium(VI) in 1 M Lithium CitrateEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2004Ermanno Vasca Abstract An Energy Dispersive X-ray Diffraction (EDXD) study of 0.3 M dioxouranium(VI) in 1 M lithium citrate at pH = 5 is reported. The data are in accordance with the existence of a predominately polynuclear complex containing four U atoms, concluded from potentiometric measurements. The uranium atoms lie at the corners of two triangles sharing one edge. Five O atoms surround each uranyl group, the uranium coordination polyhedron being a pentagonal bipyramid; four U atoms are linked through double or single O bridges. The U,U distances are 3.95 Å and 4.65 Å. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] The ,-to-, Transition in BiFeO3: A Powder Neutron Diffraction StudyADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Donna C. Arnold Abstract High-temperature powder neutron diffraction experiments are conducted around the reported ,,, phase transition (,930,°C) in BiFeO3. The results demonstrate that while a small volume contraction is observed at the transition temperature, consistent with an insulator,metal transition, both the ,- and ,-phase of BiFeO3 exhibit orthorhombic symmetry; i.e., no further increase of symmetry occurs during this transition. The ,-orthorhombic phase is observed to persist up to a temperature of approximately 950,°C before complete decomposition into Bi2Fe4O9 (and liquid Bi2O3), which subsequently begins to decompose at approximately 960,°C. [source] Neutron Powder Diffraction Study of a Phase Transition in La0.68(Ti0.95Al0.05)O3JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2006Roushown Ali Crystal structures and structural changes of the compound La0.68(Ti0.95Al0.05)O3 have been studied using neutron powder diffraction data and the Rietveld method in the temperature range from 25° to 592°C. The Rietveld profile-fitting analyses of the neutron data and the synchrotron diffraction profile revealed that the crystal symmetry of the low-temperature phase of La0.68(Ti0.95Al0.05)O3 is orthorhombic Cmmm (2ap× 2ap× 2ap; p: pseudo-cubic perovskite). The unit-cell and structural parameters were successfully refined with the orthorhombic Cmmm for the intensity data measured at 25°, 182°, and 286°C, and with the tetragonal P4/mmm (ap×ap× 2ap) for intensity data obtained at 388° and 592°C. The P4/mmm -to- Cmmm phase transition was found to be induced by tilting of the (TiAl)O6 octahedron. The tilt angle decreased with increasing temperature, reaching 0° at the Cmmm,P4/mmm transition temperature. [source] Electron Backscatter Diffraction Study of Brachiopod Shell Calcite , Microscale Phase and Texture Analysis of a Polycrystalline BiomaterialPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 5-6 2008Wolfgang W. Schmahl Abstract Electron backscatter diffraction (EBSD) is an easy to use and highly automated microdiffraction method suitable for the determination of crystallographic phase and crystallite orientation. The high level of hierarchical structural organization in the shells of marine organisms was studied. Calcite brachiopod shell materials were found to belong to three types of microstructure: nano- to microcrystalline layers of acicular crystals, fiber composites with calcite single crystal fibers with [uv0] morphological axes, and material formed by columnar crystals with [001] morphological axes selected by competitive growth. [source] Time-Resolved In Situ Diffraction Study of the Solvothermal Crystallization of Some Prototypical Metal,Organic Frameworks,ANGEWANDTE CHEMIE, Issue 4 2010Franck Millange Dr. Innenansicht: In-situ-Beugungsstudien der Kristallisation von Metall-organischen Gerüsten (MOFs) aus Übergangsmetallionen und Carboxylatliganden ergaben, dass einige Gerüste klassische Keimwachstumskinetiken zeigen, während andere über metastabile transiente Phasen entstehen (siehe Bild). [source] ChemInform Abstract: A Powder Neutron Diffraction Study of the Metallic Ferromagnet Co3Sn2S2.CHEMINFORM, Issue 19 2009Paz Vaqueiro 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Neutron Powder Diffraction Study of the Magnetic and Crystal Structures of SrFe2(PO4)2.CHEMINFORM, Issue 52 2008Alexei A. Belik 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Neutron Diffraction Study of Structural and Magnetic Properties of Monoclinic Cr5Te8.CHEMINFORM, Issue 48 2008Zhong-Le Huang 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Low Temperature Magnetization and Neutron Diffraction Study of Ca2NiWO6.CHEMINFORM, Issue 33 2008Keka R. Chakraborty 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Crystal and Magnetic Structure of Sr2MReO6 (M: Ni, Co, Zn) Double Perovskites: A Neutron Diffraction Study.CHEMINFORM, Issue 20 2008Maria Retuerto 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Synchrotron X-Ray Diffraction Study of ErMn2D2.CHEMINFORM, Issue 31 2007J. P. Maehlen 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] Neutron Powder Diffraction Study of the Orthorhombic to Monoclinic Transition in Sc2W3O12 on Compression.CHEMINFORM, Issue 25 2006Tamas Varga 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] Phase Transitions in MnO and FeO at Low Temperatures: A Neutron Powder Diffraction Study.CHEMINFORM, Issue 52 2005A. P. Kantor Abstract For Abstract see ChemInform Abstract in Full Text. [source] Neutron Powder Diffraction Study of Mn-Bearing Hematite, ,-Fe2-xMnxO3, in the Range 0 , x , 0.176.CHEMINFORM, Issue 37 2005V. Baron Abstract For Abstract see ChemInform Abstract in Full Text. [source] Temperature Dependent Neutron Powder Diffraction Study of the Laves Phase Compound TbCo2.CHEMINFORM, Issue 22 2005Z. W. Ouyang Abstract For Abstract see ChemInform Abstract in Full Text. [source] On the Mechanism of the Pressure-Induced Wurtzite- to NaCl-Type Phase Transition in CdS: An X-Ray Diffraction Study.CHEMINFORM, Issue 14 2005Heidrun Sowa Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Neutron Diffraction Study of the Antiferromagnetic Diphosphate LiFeP2O7.CHEMINFORM, Issue 41 2002Gwenaelle Rousse Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Powder X-Ray Diffraction Study of the Double Complexes [M(NH3)5Cl][M,Cl4] as Precursors of Metal Powders (M: Ir, Rh, Co; M,: Pt, Pd).CHEMINFORM, Issue 36 2002Yu. V. Shubin Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Structure of Lithium Nitride and Transition-Metal-Doped Derivatives, Li3-x-yMxN (M: Ni, Cu): A Powder Neutron Diffraction Study.CHEMINFORM, Issue 32 2002Duncan H. Gregory Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Neutron Powder Diffraction Study of Na1-xSrxTaO3 (x = 0.2 and 0.3).CHEMINFORM, Issue 23 2002S. Y. Istomin Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Neutron Diffraction Study of HfFe6Ge6 -Type ErMn6Ge6-xGax Compounds (x = 0.2, 0.4 and 1.0).CHEMINFORM, Issue 19 2002C. Lefevre Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Molecular Structure, Bonding, and Jahn,Teller Effect in Gold Chlorides: Quantum Chemical Study of AuCl3, Au2Cl6, AuCl - 4, AuCl, and Au2Cl2 and Electron Diffraction Study of Au2Cl6.CHEMINFORM, Issue 19 2001Magdolna Hargittai Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: X-Ray Diffraction Study of Ge,Bi,Te Mixed-Layer Ternary Compounds.CHEMINFORM, Issue 18 2001O. G. Karpinskii Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Crystal Structure of Superconducting K3Ba3C60: A Combined Synchrotron X-Ray and Neutron Diffraction Study.CHEMINFORM, Issue 1 2001Serena Margadonna Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Synthesis, structural and thermal studies of tetrathioureacopper(I) chloride crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2005M. Dhandapani Abstract Tetrathioureacopper(I) chloride, hereafter abbreviated as TCC, was synthesised and single crystals were obtained from saturated aqueous solution by slow evaporation (solution growth) method at room temperature. The crystals obtained are bright, colourless and transparent having well defined external faces. The grown crystals were characterized through elemental analysis, single crystal X-ray diffraction study, thermal analysis, electron spin resonance spectroscopy and Fourier Transform infrared spectroscopy. The elemental analysis confirms the stoichiometry of the compound. The single crystal diffraction studies indicate that TCC crystallises in the tetragonal lattice and the unit cell parameters are a = b = 13.4082 Å, c = 13.8074 Å, V = 2482.29 Å3, , = , = , = 90°. Space group and the number of molecules per unit cell (Z) are found to be P41212 and 8 respectively. The TG curve of the sample shows a prolonged decomposition from 210 to 628.3 °C, from which the decomposition pattern has been formulated. The endothermic peaks in the DTA curve indicate melting and decomposition of the compound at 165.2 and 633.8 °C respectively. An exothermic peak in high temperature DSC indicates a phase transition in the compound at 274.8 °C. Thermal anomalies observed in the low temperature DSC at ,163.3, ,152.0, ,141.5, ,108.3, 1.0 and 12.1 °C in the heating run and ,157.1 and ,153.9 °C in the cooling run reveal first order phase transitions in the crystal. The peaks observed at ,146.2 °C in both the heating and cooling runs suggest occurrence of a second order phase transition in this compound. The IR spectroscopic data were used to assign the characteristic vibrational frequencies of various groups present in the compound. The ESR study confirms that the copper is in the +1 oxidation state in the complex. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Solubility studies on valdecoxib in the presence of carriers, cosolvents, and surfactantsDRUG DEVELOPMENT RESEARCH, Issue 1 2004Kashappa Goud H. Desai Abstract Enhancement of the solubility of valdecoxib was examined using a series of hydrophilic carriers (mannitol, polyethylene glycol (PEG) 4000, PEG 6000, PEG 8000, and urea), surfactants (Tween-20, Tween-80, and sodium lauryl sulfate [SLS]) and cosolvents (ethanol, methanol, and glycerol) at 37°C. The solubility of valdecoxib could be enhanced significantly using PEG 4000 as a carrier, ethanol as cosolvent, and SLS as a surfactant. Because the solubility of valdecoxib increased dramatically in the presence of polyethylene glycols, these are suitable dispersing agents for preparing solid dispersions containing valdecoxib. Gibbs free energy (,G) values were all negative for all hydrophilic carriers tested, indicating the spontaneous nature of valdecoxib solubilisation. Among the cosolvents, ethanol exhibited higher solubilization potential than methanol and glycerol. As the dielectric constant of the cosolvent,water mixtures decreased, the solubility of valdecoxib increased. Finally, SLS exerted maximum solubilization of valdecoxib when compared to Tween-20 or Tween-80. The crystallinity of valdecoxib was explored by X-ray diffraction study and showed numerous crystalline peaks. Examination of surface morphology by scanning electron microscopy depicted a near spherical shape of valdecoxib with irregular surface characteristics. Drug Dev. Res. 62:41,48, 2004. © 2004 Wiley-Liss, Inc. [source] Synthesis, Structural, Thermal and Magnetic Characterization of a Pyrophosphato-Bridged Cobalt(II) ComplexEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 17 2008Oluwatayo F. Ikotun Abstract The reaction in water of CoII sulfate heptahydrate with 1,10-phenanthroline (phen) and sodium pyrophosphate (Na4P2O7) in a 2:4:1 stoichiometric ratio resulted in the crystallization of a neutral dinuclear CoII complex, {[Co(phen)2]2(,-P2O7)}·6MeOH (1), as revealed by a single-crystal X-ray diffraction study. The bridging pyrophosphato ligand between the two [Co(phen)2]2+ units in a bis(bidentate) coordination mode places the adjacent metal centers at 4.857 Å distance, and its conformation gives rise to intramolecular ,,, stacking interaction between adjacent phen ligands. Indeed, intermolecular ,,, stacking interactions between phen ligands from adjacent dinuclear complexes create a supramolecular 2D network in 1. Magnetic susceptibility measurements on a polycrystalline sample of 1 in the temperature range 1.9,295 K are typical of an overall antiferromagnetic coupling with a maximum of the magnetic susceptibility at 3.0 K. The analysis of the magnetic data in the whole temperature range allows the determination of the value of the intramolecular magnetic coupling (J = ,1.23 cm,1). The ability of the pyrophosphato ligand to mediate magnetic interactions between different first-row transition-metal ions when adopting the bis(bidentate) bridging mode is analyzed and discussed in the light of the small number of magneto-structural reports on this type of compound, bearing in mind the number of unpaired electrons and type of magnetic orbitals on each metal center. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Breaking Infinite CuI Carboxylate Helix Held by Cuprophilicity into Discrete Cun Fragments (n = 6, 4, 2)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2008Yulia Sevryugina Abstract A new copper(I) carboxylate complex with 3,5-bis(trifluoromethyl)benzoate ligands, [Cu(O2C(3,5-CF3)2C6H3)] (1), has been prepared in high yield and fully characterized. An X-ray diffraction study revealed a remarkable infinite double-helical chain motif held together by cuprophilic interactions ranging from 2.69 to 3.14 Å. Both left- and right-handed helices are present in the unit cell of the centrosymmetric structure of 1 thus making the crystalline compound racemic. Complex 1 shows bright emission at ca. 594 nm upon UV/Vis radiation in the solid state (,ex = 350 nm). The Cu···Cu contacts in 1 are easily broken in the gas phase to afford copper clusters of ascertained nuclearity upon sublimation with various polyaromatic hydrocarbons. Several polyarenes such as fluoranthene (C16H10), pyrene (C16H10), and coronene (C24H12) were selected to cover a broad temperature range from 130 to 220 °C for the gas-phase co-deposition reactions. As a result of the successive temperature increase, cleavage of the infinite copper(I) chain into [Cun(O2C(3,5-CF3)2C6H3)n] fragments of decreasing nuclearity, n = 6, 4, and 2, has been achieved. The isolation of these units represents the first instance where various polynuclear copper(I) complexes are prepared and structurally characterized for the same carboxylate ligand.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Bent and Linear Forms of the (,-Oxo)bis[trichloroferrate(III)] Dianion: An Intermolecular Effect , Structural, Electronic and Magnetic PropertiesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2003Agustí Lledós Abstract We have analyzed the great diversity of Fe,O,Fe angles, 140,180°, found in the X-ray structures of the (,-oxo)bis[trichloroferrate(III)] dianion [Cl3FeOFeCl3]2, from both experimental and theoretical points of view. Theoretical calculations show that only the linear isomer is found as a minimum on the potential energy surface. Detailed analysis of the crystal packing indicates that the angular form is due to attractive intermolecular interactions. Analysis of a selected reduced set of the 45 crystal structures retrieved from the Cambridge Structural Database allowed us to classify the bending of the [Cl3FeOFeCl3]2, dianion in three categories, depending on the balance and strength of the intermolecular O···H,X contacts. A crystal diffraction study on the bis(benzyltrimethylammonium) salt has shown both bent (144.6°) and linear (180°) forms of the (,-oxo)bis[trichloroferrate(III)] dianion. The magnetic susceptibility of this compound has been fitted by assuming two equally weighted contributions (Jang and Jlin) of the two forms, considering Jang , Jlin estimated by theoretical calculations. The obtained Jang and Jlin of ,117 and ,133 cm,1 respectively, agree well with B3LYP results. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] New Molecular Charge-Transfer Salts of TM-TTF and BMDT-TTF with Thiocyanate and Selenocyanate Complex Anions [TMTTF = Tetramethyltetrathiafulvalene; BMDT-TTF = Bis(methylenedithio)tetrathiafulvalene]EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 4 2003Marta Mas-Torrent Abstract Three new charge-transfer salts of tetrathiafulvalene (TTF)-based donors with thiocyanato- or selenocyanato-metal complex anions have been synthesised. The salts isolated were [BMDT-TTF]4[Cr(NCS)6] (1), [TM-TTF]4[Cr(NCS)6]·2CH3CN (2) and [TM-TTF]4[Cr(NCSe)6]·2CH3CN (3) [BMDT-TTF = bis(methylenedithio)tetrathiafulvalene and TM-TTF = tetramethyltetrathiafulvalene]. Single crystals of compound 1 crystallise in the monoclinic C2/c space group with a = 37.286(3), b = 10.0539(6), c = 21.069(2) Å, , = 124.348(4)°, V = 6520.9(9) Å3 and Z = 4. Compound 3 was also suitable for an X-ray diffraction study, however the anionic part, [Cr(NCSe)6], was highly disordered and the best solution gave a final R factor of 16.4%. A solution was found for the monoclinic space group C2/m with a = 13.787(3), b = 19.507(3), c = 14.735(5) Å, , = 102.90(3)°, V = 3862.9(17) Å3 and Z = 2. For compound 1 there are several S···S close atomic contacts between the donors and acceptors, but there is no discernible magnetic exchange between ions. Such an interaction was previously observed in related salts such as [TTF][Cr(NCS)4(phenanthroline)2] and [donor][M(NCS)4(isoquinoline)2] [M = Cr, Fe and donor = TTF, BEDT-TTF or TM-TTF (tetramethyltetrathiafulvalene)]. Compounds 1 to 3 are all paramagnetic semiconductors in which the magnetic susceptibility is dominated by the Cr-containing anions. The structure-function relationship, along with a comparison with related compounds, indicates that there is no long-range magnetic order because there are no ,-stacking interactions between donor and acceptor; these types of interactions are seen in all of the bulk magnets of this type in which the donor spin is magnetically coupled to the anion. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] | ||||||||||||||||||||||||||||||||||