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European Microscopy Congress 2016: Proceedings || Structure solution of the complex λ-La6W2O15
摘要： The structure solution of the complex β-Ga2O3 (β-Ga2O3) phase has been studied by a number of groups [1-3], but little detailed information has been reported due to the lack of good single crystals. The β-Ga2O3 phase has a monoclinic structure with space group C2/m and lattice parameters a = 12.23 ?, b = 3.04 ?, c = 5.80 ?, β = 103.7°. Recently, the structures of La2Ga2O7, La1.8Sr0.2Ga2O6.9 and La0.9Sr0.1Ga0.9Mg0.1O2.9 have been solved using X-ray powder diffraction (XRPD) [4-7]. The β-Ga2O3 phase has been studied by a number of groups [8-11], but little detailed information has been reported due to the lack of good single crystals. The β-Ga2O3 phase has a monoclinic structure with space group C2/m and lattice parameters a = 12.23 ?, b = 3.04 ?, c = 5.80 ?, β = 103.7°. Recently, the structures of La2Ga2O7, La1.8Sr0.2Ga2O6.9 and La0.9Sr0.1Ga0.9Mg0.1O2.9 have been solved using X-ray powder diffraction (XRPD) [4-7].
关键词： structure solution,β-Ga2O3,X-ray powder diffraction,monoclinic,lattice parameters
更新于2025-09-23 15:22:29
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Temperature Dependence of the Lattice Parameters of Cu2?–?xSe (0.03 ≤ x ≤ 0.23) Powders Fabricated by Mechanochemical Synthesis
摘要： The Cu2 – xSe (0.03 ≤ x ≤ 0.23) powders fabricated by mechanochemical synthesis have been studied by X-ray diffraction. The in situ study has been carried out for the temperature dependences of the lattice parameters, the structures, and the phase compositions of the powders in the temperature range 25–350°C. The powder compositions are shown to differ from the charge compositions and are shifted to lower copper concentrations. The estimation of peak half-widths of the cubic β phase indicates an increase in the structure imperfection after the phase transition from the α phase to the β phase of Cu2 – xSe at ~140°C. It is shown that the superpositions of the subtraction solutions (copper vacancies) and interstitials solutions (copper atoms in interstitial sites), whose proportion is changed as a function of temperature and the deviation from stoichiometry, are in the thermodynamic equilibrium in the copper selenide solid solution at room temperature. The change in the slope of the dependence of the lattice parameter of the powder Cu2 – xSe samples on the composition (0.03 ≤ x ≤ 0.23) in the temperature range 25–350°C enables the suggestion that interstitial copper atom concentration increases with temperature and deviation from stoichiometry.
关键词： phase transition,lattice parameters,mechanochemical synthesis,Cu2 – xSe,X-ray diffraction,thermodynamic equilibrium
更新于2025-09-23 15:21:01
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A simplified empirical model for predicting the lattice parameters for the cubic perovskite-related inorganic A2BX6 halides
摘要： Using multiple linear regression analysis, a simple yet efficient calculation scheme based on the Shannon effective ionic radii system has been developed for predicting the lattice parameters of the perovskite-related inorganic A2BX6 halides crystallizing in the cubic K2PtCl6 structure type.
关键词： ternary halides,lattice parameters,defect perovskites,regression analysis
更新于2025-09-09 09:28:46