An analysis of the microstructure of nanocrystalline cerium oxide produced by thermal decomposition of cerium (IV) oxide nitrate at temperatures in the range 230° to 960 °C is described. Parameters describing the breadths and shape of X-ray diffraction line profiles were obtained by means of pattern decomposition and a method based on the Voigt function was used to obtain information on the temperature dependence of the microstructure. No marked anisotropy in size and strain broadening was observed. It was found that the crystallites are on average spherical, the dimensions increasing significantly with formation temperature, while microstrains decrease with annealing temperature. The results of size determinations were compared with SEM measurements. They suggest a competition between the crystallite growth and “particle” growth processes in the initial sintering of the loosely packed cerium oxide powder.

The synthesis at 850 °C and the structural characterization of the elpasolite structure compound Cs2NaCeCl6 is reported space group Fm3m, a = 10.943(2) Å, V = 1310.4 (Å)3, Z = 4, M = 641.64, Dx = 3.252, and Dexp = 3.21. Powder diffraction data from a Rietveld structure refinement, are reported.

High-quality powder X-ray diffraction data for a well-characterised natural sample of natrolite (Na2Al2Si3O10.2H2O, space group Fdd2, Z = 8) are presented. Refined cell parameters were a = 18.2984±0.0007 Å, b = 18.6502±0.0008 Å, and c = 6.5589±0.0003 Å. The sample was characterised using thermogravimetric techniques (to determine water content), EPMA and ICP-MS (to determine composition). Available data suggest that the crystal matches the expected stoichiometry of natrolite. Our powder data show close similarity with the proposed structure of natrolite using the Rietveld method, giving R values of 8.54%, and suggest that preferred orientation is not present in the sample.

A nonlinear optical material, 4-chlorocinnamylidenyl-4′ -phenylacetophenone (C23H17ClO), 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 60° are reported. The powder diffraction data have been evaluated, and the figures-of-merit are reported. The unit cell parameters least-squares refined from 30 nonoverlapping peaks of the orthorhombic compound with a P21212 space group are a =14.756(3) Å, b = 20.647(8) Å, c = 5.840(1) Å, V = 1779.3(9) Å3, Z = 4, and Dx = 1.287 g/cm3.

An X-ray powder-diffraction pattern for boracite, Mg3B7O13Cl, is reported. Boracite is orthorhombic, space group Pca21, and the refined unit-cell parameters are a=8.557(6), b=8.553(8), c= 12.09(1) Å. X-ray powder-diffraction patterns have been calculated for the boracite-group minerals boracite, ericaite, trembathite and congolite. The calculated pattern for boracite is in good agreement with the observed pattern reported here, but the PDF entry (5-710) for boracite is missing several intense peaks. The calculated pattern for ericaite is in poor agreement with the PDF entry (29-697) for ericaite, and PDF 29-697 is for congolite, not ericaite. The calculated powder patterns presented here for these four minerals will facilitate their identification via X-ray powder diffraction. © 1995 International Centre for Diffraction Data.

Powder X-ray diffraction data for cubic La0.3Sr0.7CoO3−δ, perovskite prepared by a combustion method, using metal-EDTA complexes are reported. The cubic cell parameter is: ac = 3.8323(9)Å.

Icosahedral boron phosphide (B12P2) was directly synthesized from elemental powders by a high-temperature reaction under an argon pressure. Powder diffraction data were collected for two B12P2 samples, and diffraction patterns were compared with calculated patterns of phosphorus deficient crystals: B12+xP2−x for 0<;x<0.2. The as-synthesized B12P2 appears to be close to its ideal stoichiometry based on the consistency between the observed and the calculated values of the relative intensity for all diffraction planes below 90° 2θ.

Synthesis of high-purity, single-phase gallium nitride (GaN) powder has been achieved by reacting molten Ga with flowing ammonia (NH3) in a hot wall tube furnace. The optimum temperature, NH3 flow rate, and position of the boat in the hot wall tube furnace relative to the NH3 inlet for the complete reaction to pure GaN for our system were 975 °C, 400 standard cubic centimeters per minute (seem) and 50 cm, respectively. The X-ray diffraction (XRD) data revealed the GaN to be single phase with a = 3.1891 Å, c = 5.1855 Å, in space group P63mc, Z=2 and Dx =6.089 g cm−3. Scanning electron microscopy revealed a particle size distribution in the crushed material between 1 and 5 μm with most of the particles being ≍1 μm.

Because of their potential to induce a number of pathological diseases and their widespread industrial usage in the past, the fibrous minerals forming asbestos have been the subject of a number of studies in the past. Although quantification of asbestos minerals by optical and electron microscopy (SEM, TEM) is a routine technique in the case of dispersed airborn fibers, the detection and the quantification of small amount of fibrous minerals like chrysotile in bulk materials such as building materials is exceedingly difficult. A method for the detection and evaluation of asbestos minerals in massive samples is described, based on a combination of Rietveld and RIR (Reference Intensity Ratio) methods. Lower detection limits are about 0.5-1.0 wt % for chrysotile, depending on powder pattern, counting statistics, and matrix absorption. The chrysotile wt % determined on powder diffraction profiles collected on a conventional instrument is precise to about 1.0 wt % absolute (relative error in the range 0-10%). The technique is of straightforward application. If compared with the commonly used microscopic or spectroscopic techniques, it is of much advantage from the point of view of time, and the results are more accurate and statistically significant of the bulk material. A model for the cylindrically disordered structure of fibrous chrysotile is especially developed for the simulation of the X-ray powder patterns, and it is proposed here.

The error is investigated which results from the employment of tangential approximation in the calculation of line shift caused by specimen displacement from the recording circle in focusing systems (Guinier, Seemann–Bohlin). After an exact expression has been deduced and compared with the approximate formula in a numerical example, it is concluded that the error caused by the approximate formula may be important only in exceptional cases. The deduced exact formula is also compared with that given by Rafaja and Valvoda [Powder Diffr. 6, 200–203 (1991)] with the conclusion that both formulas are mathematically equivalent and complementary with respect to the theoretical and measured values of the diffraction angle 2θ.

Indexed X-ray powder diffraction data are reported for the semiconducting compound Ba2Cl2Cu3O4. The structure was refined by the Rietveid technique on the basis of the space group I4/mmm. Refined unit cell dimensions are a = 5.5156(1) Å, c = 13.8221(3) Å, V = 420.49 Å3Dx = 4.74 g/cm3, F30 = 129(0.0075,30), M20 = 121, Rp = 6.58, Rwp = 8.66, and RB = 4.49.

X-ray powder diffraction data are reported for the monohydrated ammonium dioxalatotitanyl (IV). The crystal system is monoclinic with space group P21/c. Refined unitcell parameters are a = 13.484(3), b = 11.325(2), c = 17.673(3) Å, and β = 126.613(8)°.

X-ray powder diffraction data for a new potassium sodium silicate Na1.3K0.7Si2O5 are reported. The sample was prepared by calcining a mixture of NaOH, KOH, and sodium silicate (SiO2/Na2O=3.54, moisture content=60%) at 873 K for 2 h. The crystallographic data obtained by using the whole-powder-pattern decomposition method are Na1.3K0.7Si2O5, monoclinic, P21/c, a =4.8426(1) Å, b = 8.6892(2) Å, c = 11.9686(3) Å, β=90.373(2)°, V=503.60(2) Å3, Z=4, Dx = 2.51 g/cm3.

A new diffraction pattern of the high-temperature and high-pressure polymorph Mg3(PO4)2-III (PDF 43-500) is given and indexed on the basis of a single-crystal structure refinement. It allows diffractogram indexing of the isostructural high-temperature and high-pressure form of Co3(PO4)2 (PDF 43-499).

Several compositions of the solid solutions (CaxSr1−x)CuO2 and (CaxSr1−x)2CuO3, both of which are found as minor phases in the high-temperature superconductors, were prepared by solid-state reaction. X-ray powder-diffraction patterns for three compositions of (CaxSr1−x)CuO2 and two for (CaxSr1−x)2CuO3 are presented.

The crystal structures of Mek[Fe(CN)6];l·mH2O where Me = Cu, Ni and Co, have been refined from X-ray (CuKa) powder diffraction data by means of Rietveld analyses in space group . The Fe and Me ions are octahedrally coordinated by C and N atoms respectively, forming three-dimensional bimetallic networks with the CN-groups as bridging ligands. The Me(l) sites (k = 2, l=1) and the Fe sites (k = 3, l = 2) are partially occupied. Water oxygens were placed in alternative, empty metal sites.