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.

Two compounds have been studied by means of powder diffraction and their unit cell parameters are reported. The monoclinic cell parameters for dimethylgermanyl-bridged bis cyclopentadienyl tetracarbonyl diruthenium are a=11.03(2) Å, b=13.65(2) Å, c=11.609(2) Å, β=105.81(1)°, Z=4, space group P21/n (No. 14), Dx=2.135 mg/m3. The monoclinic cell parameters for λ-dimethylsilyl-dicyclopentadienyl-π, π′-tetracarbonyl diruthenium, are a=11.113(3) Å, b=13.60(1) Å, c=11.674(7) Å, and β=106.00(3)°, Z=4, space group P21/n (No. 14), and Dx=1.946 mg/m3. The cells found for the two compounds are in good agreement with those obtained from single crystal X-ray diffractometry.

X-ray powder diffraction data for a new calcium zirconium phosphate Ca7Zr(PO4)6 are reported. The sample was prepared by heating mixtures of CaCO3, ZrO2, and NH4H2PO4 in prescribed molar ratios at 1623 K. Powder diffraction data were collected with a laboratory X-ray source (Cu Kα) for refinement of unit-cell parameters and intensity measurement of individual reflections. Crystallographic data were Ca7Zr(PO4)6, cubic, I-43d (No. 220), a=0.98338(1) nm, V=0.95097(3) nm3, Z=2, and Dx=3.29 Mg m−3. This compound is most probably isomorphous with eulytite.

The object was to perform simultaneous quantitative analyses of complex pharmaceutical solid mixtures by the Rietveld method. Mixtures consisting of anhydrous β-carbamazepine, anhydrous α-carbamazepine, and carbamazepine dihydrate were chosen as the model system. Lithium fluoride was used as the internal standard. Mixtures of various compositions were prepared and subjected to X-ray powder diffractometry (XRD). The XRD pattern of each mixture was analyzed by the Rietveld method and at the end of the refinement, the goodness of fit was evaluated. When the analyte concentration was high (≥20%), the relative error in the determination was <±5%. The detection of analyte was possible even when its concentration was low (<1% w/w). A unique advantage of the method is that it enables simultaneous quantitative analyses of multiple phases without the requirement of “standard curves.” © 2001 International Centre for Diffraction Data.

The outcome of the analysis of data from a Round Robin on a KCl sample is reported. The research project has led to a definition of a working protocol for the treatment of X-ray diffraction data from powders (XRPD). The protocol is based on the method of “Diffraction Instrumental Monitoring” (DIM), whose main characteristics are briefly illustrated. When experimental data are referred to the expected standard values of the lattice parameter, the method enables comparison with data obtained from differing instrumentation found in different laboratories. Application of DIM to the KCl Round Robin demonstrates the ability of DIM to effectively evaluate systematic contribution. Accuracy on the cell parameter is obtained as a direct consequence; in this application, where the knowledge of the KCl d-spacing was not a problem, the accuracy of lattice parameter is a feedback for constraining the evaluation of the effective values of the experiment-related parameters.

The crystal structure of CaZr(PO4)2 was determined from conventional X-ray powder diffraction data using direct methods, and it was further refined by the Rietveld method. The structure was orthorhombic (space group P212121, Z=4) with a=1.448 76(4), b=0.672 13(1), c=0.623 47(2) nm, and V=0.607 10(3) nm3. Final reliability indices were Rwp=6.49%, RB=2.43%, and S=1.32. The Ca atom is sevenfold coordinated, and the Ca atom and surrounding oxygen atoms form a distorted capped octahedron with a mean Ca–O distance of 0.243 nm. The ZrO7 coordination polyhedron is a distorted pentagonal bipyramid with a mean Zr–O distance of 0.216 nm. CaO7, ZrO7, and PO4 polyhedra share edges to form infinite chains with the composition [CaO3ZrO3P2O8]12− along the [010]. Individual chains are linked together, forming a two-dimensional sheet parallel to (100). These sheets are stacked in the [100] direction to form a three-dimensional structure.

Two selected members of the homologous series An+2BBn′O3n+3 (A=Sr and Ca; B and B′=Co) have been investigated for their crystal structures because of their potential applications as thermoelectric materials. A combined Rietveld refinement and spin-polarized magnetic geometry optimization technique was employed for the structural studies. Both the n=3 member, (Sr0.8Ca0.2)5Co4O12, and the n=4 member, Sr6Co5O15, have distorted hexagonal perovskite-related structures that possess one-dimensional cobalt oxide chains separated by alkaline-earth cations. The linear chains consist of one unit of CoO6 trigonal prism alternating with n units of CoO6 octahedra. Crystal structures and reference powder X-ray diffraction patterns of (Sr0.8Ca0.2)5Co4O11 [P3c1, a=9.4196(2) Å, c=19.9857(6) Å, V=825.83 Å3, and Dx=5.358 g/cm3] and Sr6Co5O15 [R32, a=9.497 64(12) Å, c=12.3956(2) Å, V=968.34 Å3, and Dx=5.455 g/cm3] are reported.

The compound Th13Te24O74 was prepared by three independent methods, namely, thermal decomposition of ThTe2O6 in oxygen and argon and direct solid-state reaction of ThO2 and TeO2. The X-ray powder diffraction patterns of the three products, by and large, are similar, except for some differences in intensities and extra diffraction lines. The thermal decomposition of ThTe2O6 was carried out in the streams of oxygen and argon by thermogravimetry at a heating rate of 5 K/min in the temperature range of 725–840 °C. The solid-state reaction of ThO2 and TeO2 (13:24) was carried out in a sealed ampoule at 700 °C. The measured density of this compound is 8.23 g/cm3. An orthorhombic lattice with unit cell parameters, a=11.310±0.005 Å, b=14.064±0.006 Å, c=9.056±0.004 Å, and volume of 1440.419±1.088 (Å)3 was determined for this compound.