The systems PbO–Bi2O3–P2O5/As2O5/V2O5 have been studied with respect to their compounds and solid solutions. A number of new compounds, particularly with high-Bi contents were found. Most of them are structurally closely related to the CaF2 and δ-Bi2O3 structures. Several binary and ternary solid solutions with P/As/V substitutions were investigated.

The structures of two high-pressure tungsten oxides, previously studied by high-resolution electron microscopy, were confirmed by Rietveld refinement based on X-ray powder diffraction data. The phases have identical stoichiometry, W3O8, and extremely narrow 00l reflections in common. The microstructure of the dominant phase was investigated by means of X-ray powder diffraction pattern decomposition. A Williamson–Hall plot revealed that all lines, except the 00l reflections, were broadened solely due to the crystallite size effect. A cylindrical model is used to describe the average form of the coherently diffracting domains. The height of the cylinder, whose axis is colinear with the crystallographic c parameter of both phases, is considered “infinite,” and the average diameter of the cylinder model is 655(22) Å. A quantitative confirmation is obtained from electron microscopy.

Y6Cr4+xAl43−x (x = 2.57); space group P63/mcm, a = 10.8601(1) Å, c = 17.6783(3) Å, V= 1805.7(1) Å3, Z=2; isostructural to Yb6Cr4+xAl43−x, (x=1.76) with two aluminium sites partially occupied by chromium (44% and 27% Cr). YCr4−xAl8+x (x=1.22); space group I4/mmm, a = 9.0299(2) Å, c = 5.1208(2) Å, V=417.55(3) Å3, Z=2, disordered variant of CeMn4Al8 with one chromium site (8f) partially occupied by aluminium (33% Al); X-ray powder diffraction data were collected on a well-crystallized multiphase sample containing 43 wt.% of Y6Cr4+xAl43−x, 27 wt.% of Y2Cr8−xAl16+x, 16 wt.% of Al, 13 wt.% of YAl3, and traces of Y2O3. Structure refinement converged at Rwp = 2.0% and RB = 3.5, 3.6% resp. for a total of 78 parameters and 1190 reflections.

A task group of the JCPDS—International Center for Diffraction Data (ICDD) was established with the charge of investigating the use of silver behenate, CH3(CH2)20COO·Ag, as a possible low-angle calibration standard for powder diffraction applications. Utilizing several data collection and analysis techniques, long-period spacing (d001) values with a range of 58.219–58.480 Å were obtained. Using the same collected data and one data analysis refinement calculation method resulted in dm values with a range of 58.303–58.425 Å. Data collected using a silicon internal standard and the same singular data analysis calculation method provided d001 values with a range of 58.363–58.381 Å.

Space group and unit-cell parameters for three 10,11-dihydro-5H-dibenz[b,f]azepine antidepressant drugs were determined. Indexed powder diffraction data for each drug are reported.

Powder-diffraction data were collected for a Chinese sample of ferrimolybdite. This mineral is orthorhombic, space group Pmmn or Pm21n, with a = 6.665(2), b = 15.423(5), c = 29.901(8), and V = 3074(1) Å3.

DISVAR93 is a collection of programs devised to process XRPD patterns with the aim of determining the parameters of systematic instrumentation and sample effects. These effects have an influence on data uncertainty and also accuracy of the adopted models describing diffraction phenomena. Such modeling is carried out through the mathematical X-ray powder-diffraction theory, while parameter optimization is achieved by using the additive property of X2 and constraining the models to converge simultaneously to the same minimum in a restrained Hilbert's space. The package has been designed to allow both user interaction as well as automatic linking of programs managed by one main menu and offer several options to satisfy individual user requirements.

The quantitative analysis of carbonate rich materials is tested with conventional and Rietveld methods. In the case of artificial mixtures of aragonite, calcite, Mg-calcite and quartz the Rietveld method provides reliable results with a maximum deviation of ±5 wt %. In the natural samples, however, the conventional methods give more reliable results in comparison to chemical and sedimentological measurements. This is caused by the peak overlap of calcite/Mg-calcite, peak roadening of the Mg-calcite, and the difficulties in the refinement of minor amounts of feldspar phases.

A nonlinear optical material 3-nitro–4-hydroxy–4′-bromobenzophenone 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 109 observed reflection with 2θ up to 90° are reported. The powder diffraction data have been evaluated, and the figures-of-merit are reported. The unit cell parameters least-squares refined from 34 nonoverlapping peaks of the orthorhombic compound with a P212121 space group are a = 7.619(7) Å, b = 27.651(5) Å, c = 5.650(7) Å, V = 1190.5(9) Å3, Z = 4, and Dx = 1.389 g/cm3.

Crystallographic data for Ni0.41Zn0.60Cu0.01Fe2.04−xSbxO4+δ (0.01≤x≤0.12) ferrites are significantly influenced by small additions of antimony. XRD analysis reveals that changes in crystal data for small Sb substitutions differ markedly from those for greater Sb substitutions. The differences are due to the contribution of the Sb ion. Complete crystal data for six solid solution compositions are reported. An X-ray powder diffraction pattern for Ni0.41Zn0.60Cu0.02Sn0.01Fe2.02Sb0.02O4+δ is given.

The compounds BaR2O4, (R = Pr, Tb), where R are two of the less frequent trivalent lanthanides, have been prepared under reducing atmosphere from mixtures of BaO2, the R metals, and the oxides Pr2O3 and Tb4O7, respectively. The crystal structure of BaR2O4 have been refined from X-ray powder diffraction data by the Rietveld method of profile analysis using 31 parameters in each case. Both oxides are orthorhombic, isotypic with SrY2O4, of the perovskite-related CaFe2O4 structure type, S.G. Pnma (No. 62), Z = 4, a = 10.6113(8), b = 3.6303(3), c = 12.485(1) Å, and V = 480.93(5) Å3 for R = Pr; and a = 10.4282(8), b = 3.4893(3), c = 12.1809(6) Å, and V = 443.22(3) Å3 for R = Tb. The R–O distances vary between 2.15(6) to 3.40(6) Å for R = Pr, and between 2.15(3) to 2.91(5) Å for R = Tb.

This paper describes a straightforward method for the identification of the Miller indices associated with the face of a crystal of low symmetry. The method relies on orienting a crystal face parallel to the sample holder in the goniometer of a powder diffractometer. An intense diffractogram resulting from a single family of lattice planes parallel to the crystal face is obtained. The application of silicon powder to the surface of the crystal provides a means to correct 2Θ values for any misalignment of the crystal face. Calculated 2Θ and intensity values are used to assign the reflections from the corrected single-crystal diffractogram to a particular set of related lattice planes. In this paper are listed the corrected experimental 2Θ and intensity values for a particular face of a large single crystal of monoclinic hydroxylapatite and the theoretical 2Θ and intensity values for the h00 set of planes. Comparison of these parameters leads to the unambiguous assignment of that particular crystal face to the h00 Miller index.

A perfect general purpose standard specimen for high accuracy line-profile analysis is shown to be an illusion. Balancing the partly contradictory requirements, an optimum standard specimen for a parafocusing diffractometer is developed. To obtain the optimum standard specimen, a 5–10 μm particle size fraction is taken from the NIST certified Si powder SRM640a, about 1.5 mg/cm2 of this powder is uniformly deposited on a (510) oriented Si single-crystal wafer and the assembly is heat treated for 2 h at 1273 K to remove lattice imperfections. All procedures necessary are precisely given, easily applicable, and reproducing. For the present standard specimens, the random errors due to crystal statistics are quantified and shown to be acceptable for spinning specimens; the systematic errors due to residual size and transparency broadening are determined semi-empirically and can be eliminated, if desired. Thus the proposed optimum standard specimen allows the determination of instrumental line profiles free from systematic errors and with random errors in the line width of the order of 0.001 °2θ, allowing a full use of the capacities of modern diffractometers and data evaluation procedures.

Two complexes of gallium with 3-hydroxy-4-pyrones were synthesized as potential pharmaceutical compounds for oral administration. These compounds were analyzed by powder X-ray diffraction followed by computer indexing of the data. The first compound, tris(3-hydroxy-2-methyl-4-pyronato)gallium [Ga(C6H5O3)3], was found to be orthorhombic, a = 18.500(2), b = 16.948(2), c = 12.012(2) Å, V = 3766(1) Å3, Z = 8, Dm = 1.56(5), Dx = 1.570. The compound appears closely analogous to a similar compound containing Al instead of Ga, which crystallizes in space group Pbca. The second compound, tris(3-hydroxy-2-ethyl-4-pyronato)gallium [Ga(C7H7O3)3], was found to be monoclinic, a = 31.634(2), b = 8.7662(5), c = 7.8982(5) Å, β = 103.240(6)°, V = 2132.0(5) Å3, Z = 4, Dm = 1.50(5), Dx = 1.517, with a primitive space group.