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The structures of SmAlSi and SmAlGe were determined by the powder diffraction method. These compounds have a tetragonal structure of LaPtSi type, which is a ternary substitutional variant of α-ThSi2. Both prototype structures have the same extinction rules, and as a result, the choice of the structural type must be based on very careful examination of the peak intensities. This was done with the aid of a Rietveld refinement, which indicates a better fit of the LaPtSi structure.
Order-disorder transformations were studied in annealed and high-energy ball-milled near-equiatomic FeCo alloys. X-ray diffraction with Co Kα radiation enables to follow disordering with milling time because of anomalous dispersion.
The structure of a new iodate, (LiFe1/3)(IO3)2, has been determined. The new compound has a hexagonal structure with the lattice parameters a=5.4632(2) Å, c=5.0895(6) Å, Z=1. The density is 4.70 g cm−3. Rietveld refinement confirms that the compound has a space group of P63 (173). Fe and Li atoms randomly distribute on the 2a cation site.
A nonlinear optical material, N-(p-methoxy benzoyl)-N′(o-methyl phenyl) thiourea (C16H16N2O2S), has been characterized by X-ray powder diffraction. Experimental values of 2θ corrected for systematic errors, relative peak intensities, values of d, and the Miller indices of 90 observed reflections with 2θ up to 88° are reported. The powder diffraction data have been evaluated, and the figures-of-merit are reported. The least-squares refined unit cell parameters are a=26.7079(3) Å, b=6.7995(9) Å, c=19.2845(1) Å, β=121.39(4), V=2989.42(3) Å3, Z=8, Dx=1.334(8) g/cm3, space group P2(3).
Three phosphates, MIBaIn2(PO4)3 with MI=Na, K, Cs, isostructural to the langbeinite structure, have been studied from powder diffraction data collected with monochromatic radiation obtained from a conventional X-ray source. Precise powder data are reported, as well as cell parameters, i.e., a=10.026 08(9) Å, a=10.121 57(13) Å and a=10.226 94(9) Å for MI=Na, K and Cs, respectively. A Rietveld refinement has been carried out (space group P213), with final RF factors, 0.061, 0.041 and 0.027, and Rwp factors, 0.196, 0.142 and 0.129, for MI=Na, K and Cs, respectively. There are two octahedrally coordinated In3+ ions in the asymmetric unit and the final refinements suggest disorder on the two sites of the MI/Ba sublattice.
The phases developed upon annealing of ZnSe, CdSe, and CdS semiconductors in air are investigated applying X-ray qualitative and quantitative phase analysis. The compositions of the thermally grown oxides over the 373–773 K temperature range are found to be ZnO and ZnSeO3 for ZnSe, CdSeO3 for CdSe and CdSO4 and Cd3O2SO4 for CdS. The percentage phase abundance of each phase is determined at each temperature applying a standardless method. At all temperatures, the oxides are predominantly ZnO with about 10% ZnSeO3 at 773 K in case of ZnSe and CdSO4 with about 9% Cd3O2SO4 at 773 K in case of CdS. The rate of oxidation with temperature is found to be nonlinear for the three chalcogenides. CdS is found to be more resistible for oxidation than CdSe and ZnSe.
ZnGa2Te4 was found to crystallize in a defect tetrahedral structure with possible space group I4(82) with Z=2. Complete X-ray powder diffraction data were obtained and the unit cell parameters a and c and X-ray density were calculated. These were a=0.5930(1) nm, c=1.1859(3) nm, and Dx=5.7×103 kg/m3.
Powder X-ray diffraction (XRD) data were collected for La0.65Sr0.35MnO3 prepared through an alternative method from a stoichiometric mixture of Mn2O3, La2O3, and SrO2, fired at 1300 °C for 16 h. XRD analysis using the Rietveld method was carried out and it was found that manganite has rhombohedral symmetry (space group R3c). The lattice parameters are found to be a=5.5032 Å and c=13.3674 Å. The bond valence computation indicates that the initial inclusion of Sr occurs at higher temperature.
A new zinc phosphate was synthesized by the hydrothermal reaction of zinc oxide and phosphoric acid in the presence of 1,4-diaminebutane. The formula of the product is (ZnPO4)4(H3PO4)2(C4N2H14)2 and crystallizes in the triclinic system with a=8.6590(3) Å, b=10.3467(3) Å, c=8.3910(3) Å, α=102.180(2)°, β=93.676(2)°, and γ=88.203(2)°.
X-ray powder diffraction data for Ba0.5Sr0.5Co0.8Fe0.2O3−δ are reported. The powder was prepared using a metal-EDTA complexing method. The XRD data could be fitted with a primitive cubic unit cell in space group Pm3m (No. 221). The Rietveld refined unit cell parameter is ac=0.398 30(3) nm with Z=1 and Dx=5.75 g/cm3.
The X-ray powder diffraction pattern for a bridgehead heterocyclic system was determined. 2-exo-(β-pyridyl)-6-exo-phenyl-7-oxa-1-azabicyclo[2.2.1]heptane, C16H16N2O, is triclinic with refined unit cell parameters a=1.1012(2), b=1.3950(2), c=1.0074(3) nm, α=111.09(2)°, β=104.97(2)°, γ=77.38(2)°, V=1.3813(3) nm3, Z=4, and Dx=1.212 g/cm3 with space group P-1 (No. 2).
A previous paper portrayed sample preparation by fusion methodology and the XRF analysis conditions for the calibration of cement materials [Bouchard et al., 2009. “Global cement and raw materials fusion/XRF analytical solution,” Adv. X-Ray Anal. 53, 263–279]. The results of two well known cement chemical analysis Standard Methods were also presented. These results proved that this robust analytical method is able to qualify by the ASTM C114 [ASTM C114-08 (2008). “Standard test methods for chemical analysis of hydraulic cement,” Annual Book of ASTM Standards Vol. 04.01 (ASTM International, West Conshohocken, PA), pp. 150–157)] and ISO/DIS 29581-2 [Draft Standard, 2007-07 (2007). “Methods of testing cement—Chemical analysis of cement—Part 2: Analysis by X-ray fluorescence” ISO/DIS 29581-2, 2007, pp. 1–30]. This robust analytical method was developed using an automated fusion instrument for the sample preparation and a WDXRF spectrometer for the determination of all elements of interest relating to the cement industry. This method was used to prepare finished products, process materials, as well as a very large range of raw materials. The first part of this second paper examines all the XRF analysis conditions for the calibration of the raw materials using the robust fusion sample preparation methodology as well as the numerous reference materials (RMs) used for this analytical application. All interesting results will be presented. The second part of this paper reveals the rapid analytical method results using sample preparation by fusion on nonignited samples. It will also be proven that this faster method, combined with the WDXRF spectrometer, complies with both cement analysis Standard Methods: ASTM C114 and ISO/DIS 29581-2.
Magnesiumchromite, MgCr2O4, undergoes a structural transition from a cubic spinel structure [space group Fd3m, a=8.32768(4) Å at 16 K] into a tetragonal distorted structure [space group I41/amd, a=5.89199(5) Å, c=8.31677(8) Å at 10 K], isotypic with Hausmannite, Mn3O4. This phase transition is translationengleich and takes place very close or at the antiferromagnetic ordering temperature.
The effects of proper drying and grinding of [Fe(Htrz)3](ClO4)2⋅1.85H2O specimens on the quality of X-ray powder patterns are illustrated (Htrz=1H-1,2,4-Triazole). A procedure is suggested to achieve high-quality, reproducible X-ray powder patterns of the compound. The observed powder diffraction data of the compound are reported together with preliminary indices calculated for a monoclinic system with cell parameters a=15.8160 Å, b=20.6134 Å, c=13.0321 Å, β=103.83° and Volume=4125.633 Å3, with reliability factors: M15=10.4, F15=22.0 (0.0100; 68) and space group P21/m. This compound is very similar to the compound [Cu(Hyetrz)3](ClO4)2⋅3H2O and a comparison is made between the cell parameters of the two compounds
Diffraction peak profiles broaden due to the smallness of crystallites and the presence of lattice defects. Strain broadening of powders of polycrystalline materials is often anisotropic in terms of the hkl indices. This kind of strain anisotropy has been shown to be well interpreted assuming dislocations as one of the major sources of lattice distortions. The knowledge of the dislocation contrast factors are inevitable for this interoperation. In a previous work the theoretical contrast factors were evaluated for cubic crystals for elastic constants in the Zener constant range 0.5≤Az≤8. A large number of ionic crystals and many refractory metals have elastic anisotropy, Az, well below 0.5. In the present work the contrast factors for this lower anisotropy-constant range are investigated. The calculations and the corresponding peak profile analysis are tested on ball milled PbS and Nb and nanocrystalline CeO2.
In this work we present results of X-ray diffraction using powder method, on natural alexandrite samples from Minas Gerais State (Brazil), as a function of a sequence of annealing. From these measurements we determine lattice parameters before (a=9.405 Å, b=5.471 Å, c=4.409 Å) and after annealing, and its structure is confirmed as orthorhombic. Measurements done after an annealing of 15 minutes at 700 °C and for 5 hours at 1000 °C indicate the migration of atoms present in the sample through different phases, which were also identified by Microprobe Analysis (WDS). However we have verified that such migration does not modify the structure. X-ray diffraction measurements have been carried out in conjunction with optical absorption in the UV–Vis as a function of annealing.