Papers by Keyword: Crystal Structure

Abstract: A large defective troilite (Fe0.9V0.1)0.82S is prepared by a sealed silica-tube method at 800oC and characterized by a powder X-ray diffraction method and using a magnetic property measurement system. The crystal structures of a defective troilite and non defective troilite are analyzed by Rietveld method. The large defect enhances the Fe-Fe pairing and suppresses the waving of Fe-chain along c-direction. The antiferromagnetic property is observed on both troilites. The spin-flip transition temperature of the large defective troilite is 9K.

Abstract: We succeeded in synthesizing single crystals of a novel nickel sulfate Ni2-δSO5 by a hydrothermal method. A single-crystal X-ray diffraction revealed a tetragonal structure with lattice constants, a = 5.184 Å and c = 12.91 Å. In this structure, one-dimensional chains composed of face-shared NiO6 octahedra elongate along the a axis and the b axis alternately, constructing a ‘log-cabin’ type framework where neighbor chains lying orthogonally to each other are connected by SO4 tetrahedra. A detailed refinement of the structure suggested that the site occupancy of Ni is only 63%, corresponding to δ ≈ 2/3. Furthermore, X-ray oscillation photographs exhibit diffuse-scattering patterns probably arising from a short-range order of the Ni defects. Magnetic susceptibility revealed an antiferromagnetic transition accompanied by a weak ferromagnetism at 17 K.

Abstract: . A series of gels with 3Al2O3•2SiO2 were prepared by Sol-gel method and heated at several temperatures for 2 h to synthesize Ti, Fe-doped mullite. The received powers with highest amount of TiO2 and Fe2O3 additive in range of 3.7-5.6 % and 12.5-15.9 % respectively as starting materials were characterized using X-ray powder diffraction (XRD), scanning electron microscopies (SEM) and energy dispersive spectrometry(EDX). Fe3+ and Ti4+ cation has been incorprated into the crystal lattice of mullite unevenly. The overall trend of Ti, Fe-doped mullite powers with additive amount changing is Δa>Δb>Δc(Except sample 5.6Ti-1350 is Δb>Δa>Δc owing to its excess amount of TiO2), and the relative change of Ti, Fe-doped mullite powers is Δc（%）>Δb（%）>Δa（%）(Except sample 5.6Ti-1350 and 15.9Fe-1350 is Δb（%）>Δc（%）>Δa（%） with the maximum amount of dopant ions).

Abstract: The reaction of 2-acetyl-2'-chloroacetanilide (L) with rare earth nitrates in CH₃CH₂OH followed by recrystallization in CH₃CH₂OH gave rise to colorless block crystals materials. The complexes and ligand were analyzed by FAB, elemental analysis(C, H, N), FT-IR spectra, TG-DTA, molar conductivity and X-ray single crystal diffraction. The fluorescence properties of ligand and the Eu (Ⅲ) complex also have been investigated. The results of crystal structure and spectral data show that the rare earth ions coordinated with oxygen and nitrogen atoms of the ligand, the nitrate and coordinated water molecules. The Eu (Ⅲ) complex material shows characteristic red emissions.

Abstract: The polyhedral crystals, octahedral crystals and cube crystals of Zinc hydroxystannate (ZHS) were prepared by the homogeneous precipitation synthesis method. The organic compounds, PEG-400, β-cyclodextrin (β-CD) and L-alanine were added in the reaction systems to control the crystal structure. The crystal structure and morphology of products were characterized by SEM and XRD. The crystal structure of all products could be attributed to the cubic ZnSn(OH)₆ by the XRD analysis. The SEM pictures of the products were different with the change of organic compounds. The FTIR spectrum indicated the ZHS without organic residual and the possible formation mechanism was discussed.

Abstract: Copper nitride films were prepared by reactive magnetron sputtering on glass sheets at different deposition conditions. The surface morphology of the films was evaluated by a scanning electron microscope (SEM). The SEM images demonstrate that the films have a compact structure. The structure of the films was characterized by X-ray diffraction (XRD). We focused on the influence of preparation parameters on the adhesion and electrical properties of the films. The metallurgical microscope results indicate that the adhesion of the films enhances with increasing deposition power. The current-voltage (I-V) measurement results show that the resistivity of the films increases with the increasing lattice constants.

Abstract: The effect of MnO₂ addition (0–2.0 mol%) on the densification, crystal structure, and ionic conductivity of Ce_0.8Sm_0.2O_1.9 (SDC) was studied. The addition of MnO₂ promotes densification, reducing sintering temperature by ~150°C. X-ray diffraction analysis showed that all the samples exhibit a fluorite structure. Impedance spectroscopy measurements indicated that SDC with appropriate ratio of MnO₂ addition has higher ionic conductivity and lower activation energy compared with that of SDC. As the addition amount of Mn increases up to 1.0 mol% [(Ce_0.8Sm_0.2O_1.9)_0.99+(MnO₂)_0.01], the sample attains the highest ionic conductivity, about 35% higher than that of SDC at 600°C. In addition, Mn addition has little effect on bulk conductivity, but a marked influence on grain boundary behavior is observed.

Abstract: A new Ca(II) complex material has been prepared and characterized by elemental analysis, IR and single-crystal X-ray diffraction. The results showed that the compound the calcium ion lies in seven-coordinated environments, belonging to monocapped trigonal prism geometry. The complex formed one dimensional chain structure through intramolecule and intermolecule hydrogen bonds and π-π stacking interaction. The antibacterial assay of the Ca(Ⅱ) complex was tested using a modified version of the 2-fold serial dilution method. The results show that the complex shows considerable antibacterial activity against escherichia coli, bacillus subtilis and staphylococcus white.

Abstract: The evolution of the magnetism as a function of the particle size is reported here for the ZnFe2O4 nanoparticles. A combination of neutron powder diffraction down to 1.5 K and magnetization measurements suggest that nanoparticles of sizes greater than about 100 nm exhibit bulk like behavior. The size dependence on magnetism can be explained by the rearrangement of the cations on the interstitial sites of the spinel cell.