A nonlinear optical material, N-(p-methoxy benzoyl)-N′-(p-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 94 observed reflections with 2θ up to 66° are reported. The powder diffraction data and the figure-of-merit are reported. The least-squares refined unit cell parameters are a=25.3291(3) Å, b=11.9478(1) Å, c=10.1407(4) Å, β=103.10(2)°, V=2988.97(6) Å3, Z=8, Dx=1.335(0) g/cm3, with space group P21(4).

CaMnO3 is a parent compound for various manganite systems exhibiting useful physical properties. Therefore, its structural and elastic properties are of general interest. In this paper, P–V equation of state of stoichiometric CaMnO3 is determined using energy dispersive X-ray diffraction. The measurements were carried out at a synchrotron beamline F2.1 (Hasylab, DESY) with samples compressed in a cubic-anvil diffraction press, MAX80, for pressures ranging up to 4.84 GPa. The experimental bulk modulus of CaMnO3, derived from the variation in the unit-cell volume with pressure by fitting the Birch–Murnaghan equation of state, is 154.4(3.3) GPa. The results are discussed on the basis of experimental and theoretical data for CaMnO3 and related compounds.

The performance of a tapered, monocapillary optic was compared to double-pinhole optics by measuring the intensity and widths of powder diffraction peaks generated using Cr Kα and Cu Kα X-rays (46 kV, 46 mA). A microdiffractometer and curved image-plate system was used to collect diffraction patterns displayed by an alumina intensity standard. A monocapillary optic with a 20 μm beam width (measured at half the maximum intensity, FWHM) was compared to collimating pinhole optics with two apertures: one with 30 μm diameter pinholes and another with 50 μm pinholes. The average, integrated intensity of the diffraction peaks in the patterns collected using the 20 μm monocapillary optic was 6 to 7 times greater than the average diffraction intensity obtained with the 50 μm pinhole collimator and 25 times greater than the intensity obtained with the 30 μm collimator. The average increase in the FWHM of the diffraction peaks in the patterns obtained with the monocapillary optic was ∼2 times greater than the pinhole collimators.

Five transition metal derivatives of maleic acid with general formula, M2+(C4H3O4−)2⋅4H2O (M2+=Mn, Fe, Co, Ni, and Zn) were prepared by slow evaporation of the aqueous solution at room temperature. Their X-ray powder diffraction patterns were recorded and evaluated. These materials are isostructural and crystallize in a triclinic unit cell. The volume of the cells vary linearly between that of the Ni complex [V=314.65(7) Å3: a=5.1769(8) Å, b=7.317(1) Å, c=9.140(2) Å, α=108.42(2)°, β=104.61(1)°, γ=92.87(1)°] and the volume of the Mn-derivative [V=330.30(8) Å3: a=5.322(1) Å, b=7.375(1) Å, c=9.752(2) Å, α=115.48(2)°, β=106.64(2)°, γ=86.63(2)°].

An organic adduct nonlinear optical material m-nitrobenzoic acid⋅diethanolamina (C11H16N2O6) 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 56 observed reflections are reported. The powder diffraction data have been evaluated, and the figure of merit was found to be F30=57.9 (0.0108, 48). The unit cell parameters were refined by a least-squares fit with a Cc space group and a=22.973(5) Å, b=4.6657(6) Å, c=15.023(3) Å, β =124.45(1)°, V=1327.75 Å3; Z=4, Dx=1.37 g/cm3. The powder diffraction results are in agreement with those obtained from single crystal structure data.

An experimental X-ray diffraction (XRD) study of calcium salts of four carboxylic acids is presented. Calcium salts of propionic, butyric, valeric, and caproic acids were synthesized mixing in a mortar Ca(OH)2 with the liquid acids. Measuring the thermogravimetric analysis curves it was determined that the salts were actually monohydrates. The densities of the synthesized samples were measured using a density gradient column. The measured values for the densities were as follows: Dm(propionate)=1.38 g/cm3, Dm(butyrate)=1.30 g/cm3, Dm(valerate)=1.26 g/cm3, Dm(caproate)=1.22 g/cm3. The XRD analysis revealed that these compounds have monoclinic cells with symmetry described by the P21/a space group. Calcium propionate hydrate has cell parameters: a=2.437 51(5) nm, b=0.681 24(1) nm, c=0.591 43(1) nm, β=95.320(2)°. For calcium butyrate hydrate the cell parameters are: a=2.966 84(8) nm, b=0.680 74(2) nm, c=0.589 29(2) nm, β=95.442(3)°. The cell parameters for calcium valerate hydrate are: a=3.566 36(4) nm, b=0.682 49(1) nm, c=0.592 77(1) nm, β=107.280(1)° and for calcium caproate hydrate a=4.180 30(5) nm, b=0.682 61(1) nm, c=0.592 13(1) nm, β=110.230(1)°. The calculated density values from the XRD results, taking into account that the number of chemical formulas in the unit cell equals four, agree very well with the measured ones. It was established that the unit cell parameter a grows with the increase of the number of carbon atoms in the aliphatic chain, while parameters b and c remain almost constant. This is an indication of the stacking layer character of the structure as has been suggested for calcium stearate monohydrate. This fact points to the possibility of the refinement of the crystalline structures taking as the starting point the reported structure for calcium stearate monohydrate.

Polycrystalline lead iodide, PbI2, was recrystallized from hot water to reproducibly obtain flat plate-like crystals, which manifested extreme preferred orientation greatly favoring the 001, 002, 003, and 004 planes. Polycrystalline samples of PbI2 were intercalated with tripropylamine, simultaneously producing a “new” intercalate 001 peak at 7.791°2θ (d=1.1347 nm) and diminishing the host PbI2 001 peak at 12.67°2θ (d=0.6980 nm). This is consistent with large increases in the c direction of the unit cell associated with inserting a guest between adjacent iodide layers of the host PbI2. Experimental powder diffraction results are compared to theoretical values calculated using CRYSTALMAKER and CRYSTALDIFFRACT software

Coatings of plasma sprayed hydroxyapatite (HAp), incubated in simulated body fluid for periods varying from 1 to 56 days, were characterized using conventional laboratory X rays. Quantitative phase analysis, employing TOPAS software, showed an opposite trend in the two main phases of the coating, viz., HAp and tetracalcium phosphate (TTCP). The former increased within the first 7 days of incubation whilst the latter decreased during the same period; both phases stabilized with further incubation. The crystallinity of the coatings exhibited a trend similar to that of HAp i.e., an increase in the early stages of incubation stabilization with further incubation. Results of residual stress determined with Bruker’s D8 Discover and analyzed with LEPTOS software, showed both the normal stress tensor components, σ11 and σ22, to be tensile, relaxing significantly in the early stages of incubation before stabilizing with further incubation.

The family of zeolitic imidazolate framework (ZIF) compounds is efficient sorbent materials that can be used for catalytic, ion exchange, gas storage, and gas separation applications. A high-resolution reference X-ray powder diffraction pattern for one of the ZIF members, bis(2-methylimidazolyl)-zinc, C8H10N4Zn (commonly known as ZIF-8), was determined using synchrotron diffraction data obtained at the Advanced Photon Source (APS) in Argonne, IL. The sample was confirmed to be cubic I-43m, with a = 17.01162(6) Å, V = 4932.08 Å3, and Z = 12. The reference X-ray powder diffraction pattern has been submitted for inclusion in the Powder Diffraction File (PDF).

A detailed neutron powder diffraction study of the atomic structure of α-Bi2O3 at high temperatures using the Rietveld method was performed to clarify the nature of the unusual magnetic behavior and the origin of the high temperature dielectric anomalies of α-Bi2O3 in the temperature interval 300–700 K. Analysis of obtained experimental data shows that there are no evidence of a structural phase transition in α-Bi2O3 between 295 and 660 K. The observed high temperature dielectric anomalies in α-Bi2O3 are evidently governed by changes in the electron subsystem of the bismuth oxide.

Ge–Si inverted huts, which formed at the Si∕Ge interface of Si∕Ge superlattice grown at low temperatures, have been measured by X-ray diffraction, grazing incidence X-ray specular and off-specular reflectivities, and transmission electron microscopy (TEM). The surface of the Si∕Ge superlattice is smooth, and there are no Ge–Si huts appearing on the surface. The roughness of the surfaces is less than 3 Å. Large lattice strain induced by lattice mismatch between Si and Ge is found to be relaxed because of the intermixing of Ge and Si at the Si∕Ge interface.

A simple ashing procedure for a mixture containing kaolinite and chrysotile is described that converts kaolinite to amorphous metakaolinite while retaining the diffraction intensity of chrysotile. This ashing procedure removes the X-ray diffraction (XRD) pattern overlap between kaolinite and chrysotile that can interfere with the analysis of even high concentrations of chrysotile. Samples are ashed at 460 °C in a muffle furnace for 40 h to completely convert kaolinite to metakaolinite. The complete conversion of 1 g of kaolinite under these conditions was determined for two standard kaolinite samples from Georgia, KGa-1 and KGa-2. Two of the most common types of commercial chrysotile, long-fiber Canadian and short-fiber Californian chrysotile, are demonstrated to retain diffraction intensity after ashing at 460 °C. Both chrysotile samples have the same integrated intensity for the (002) reflection prior to ashing, although the peak breadths for the two samples are quite different. Ashing at 480 and 500 °C reduces the diffraction intensities of both chrysotile samples by 15%, and broadens the peaks by approximately 3%. Using the prescribed ashing procedure and x-ray diffraction with an internal corundum standard, two kaolinite-bearing building materials containing chrysotile near 0.01 mass fraction were analyzed. The ashing procedure has additional advantages in reducing some samples to powders and removing volatile components, thereby eliminating some sample preparation procedures and concentrating any chrysotile present in the sample. The removal of volatile components improves the sensitivity of XRD analysis to concentrations below 0.01 mass fraction chrysotile.

High-resolution powder X-ray diffraction has been used to determine the crystal structure of silver behenate, [Ag(O2C(CH2)20CH3]2. Using CASTEP density functional plane wave pseudopotential techniques to obtain an optimized structural model, Rietveld refinement of the structure gives Rwp = 8.66%. The unit cell is triclinic, space group P1, with cell dimensions of a = 4.1769(2) Å, b = 4.7218(2) Å, c = 58.3385(1) Å, α = 89.440(3)°, β = 89.634(3)°, γ = 75.854(1)°. The structure is characterized by an 8-membered ring dimer of Ag atoms and carboxyl groups with a fully extended all-trans configuration of the alkyl side chains. The dimers are joined by four-membered Ag-O rings creating a polymeric network, giving rise to one-dimensional chains along the b-axis. This structure is supported by EXAFS measurements of the local structure around the silver atoms and IR measurements.

In order to better characterize metal soaps found in paint films or on metal surfaces, several metal soaps were synthesized and their X-ray powder diffraction patterns measured. Metal soaps were obtained from four different fatty acids found in drying oils, two saturated (palmitic and stearic acids) and two unsaturated (oleic and linoleic acids), and from copper, zinc, and lead, three metals that are typically found in metal alloys and paint systems. X-ray powder diffraction data are reported for the following compounds: palmitic acid, stearic acid, zinc palmitate, zinc stearate, zinc oleate, zinc linoleate, copper palmitate, copper stearate, copper oleate, lead palmitate, lead stearate, and lead oleate. Features that are characteristic of specific compounds were observed. Soaps obtained from different fatty acids with the same metal ion show differences, as do soaps obtained with the same fatty acid but with different metal ions. Differences were observed when X-ray powder diffraction data obtained for stearic acid and zinc stearate were compared to published data for these two compounds (PDF 38-1923 and 5-0079, respectively). In the case of stearic acid, differences could be explained by the fact that the specimen reported previously in PDF 38-1923 was likely contaminated with palmitic acid. In the case of zinc stearate, low angle data were missing from the original pattern PDF 5-0079 and peaks that were reported in other angular regions in fact consisted in more peaks that were not resolved due to broadening.

Two XRD specimen holders we designed for use with highly radioactive specimens are described. An injection mold was fabricated to allow inexpensive production of one of the holders. These holders are suitable for single-time use. The ease of use and disposable nature of this holder resulted in a dramatic reduction in personnel exposure and an uncontaminated diffraction unit. A second holder, based on the design of the first, is used to obtain XRD patterns from powders where preferred orientation is an issue and from clays. Both holders result in negligible background, since the specimen is essentially levitated in the X-ray beam. This is a benefit over other methods, such as collodion, that introduce significant background to the XRD pattern.