The employment of the Debye function to model line profiles in the powder diffraction pattern from small crystallites is briefly reviewed. It is also demonstrated that for the case of very small spherical particles, it is necessary to average patterns from multiple constructions of the particle to have complete agreement with reciprocal space models. In doing so it is demonstrated that the technique of Debye function analysis is best suited for systems with only a few possible atomic arrangements.

The crystal structure of the new ternary phase CuSnTi is determined by full profile Rietveld analysis of the powder diffractogram. 104 reflections were refined to a final RBragg value of 5.60%. CuSnTi crystallizes with the spacegroup P63/mmc and is isostructural to InNi2. The lattice parameters are a=0.439 555(5) nm and c=0.601 505(9) nm.

The compounds BaR2O4, where R = La, Nd, Sm, Gd, Eu, Dy, Ho and Er have been prepared from a stoichiometric mixture of BaCO3 and lanthanide oxides, and characterized by X-ray powder diffraction. Standard X-ray patterns of these phases were prepared. In general, BaR2O4 crystallizes in the pervoskite-related CaFe2O4 structure which is orthorhombic with a space group Pnam. The cell parameters of these compounds from R = Er to La range from 10.3729(12) to 10.668(2) Å for a, 12.0699(11) to 12.642(2) Å for b, from 3.4356(4) to 3.7037(10) Å for c, and from 450.14(5) Å3 to 499.51 Å3 for V respectively. A monotonic, linear relationship is obtained when V is plotted against the cube of the ionic radius of R. When R = Tm, Lu and Yb, the BaO·R2O3 composition produced the mixture Ba3R4O9 and the unreacted lanthanide oxide. Under the present experimental conditions, the compound BaRO3 was the predominant component when R = Ce, Pr, and Tb.

Powder X-ray diffraction data are reported for RE6UO12 (RE=Eu, Gd, and Dy). The powders were prepared by a solution combustion method using urea as fuel. All compositions exhibit a rhombohedral structure with hexagonal unit cell parameters of a=1.012 67 (9) nm, c=0.9601 (1) nm for Eu6UO12; a=1.008 78 (6) nm, c=0.954 24 (7) nm for Gd6UO12; and a=0.998 06 (7) nm, c=0.944 03 (8) nm for Dy6UO12. The diffraction patterns of all the compounds are indexed on the R3¯ space group with Z=3. The a and c values decrease with increasing atomic number of the rare earth ion.

Developments in X-ray analysis, and advances in scientific research, have dramatically influenced the types of data now considered suitable for inclusion in the Powder Diffraction FileTM (PDF®). Initially, the PDF was geared towards the identification of unknown crystalline materials by comparison of d-spacings and peak intensities. Today, the International Centre for Diffraction Data (ICDD) maintains and continuously enhances the quality and content of the PDF database to better provide customers and scientists with a comprehensive reference source that supports their needs, and interests. The events that initially led to the inclusion of crystalline polymer data to the PDF have recently been amended to also encompass semi-crystalline and amorphous polymeric materials as well. This paper discusses the resultant updates being made to the PDF in support of this new data form, and also highlights several features and benefits of providing this data to PDF users.

Since the discovery of the superconductivity in Ba2YCu3 O7-x, the system Ba-Y-Cu-O has generated vast interest. The presence and the properties of the intermediate phases were examined, and the existence of the BaY2O4 phase was confirmed.

We have determined the crystal structure of this material from powder data; it is orthorhombic, Pnma (no 62) with a = 10.394(3) Å, b = 3.450(1) Å, c = 12.113(4) Å, isotypic with SrY2O4 (CaFe2O4-type). The observed and calculated intensity values are reported together with the powder diffraction data, obtained both by Guinier and diffractometer methods.

The crystal structure of the common expectorant guaifenesin, 3-(2-methoxyphenoxy)-1, 2-propanediol (C10H14O4) was solved by applying Monte Carlo simulated annealing techniques to synchrotron powder data, and refined using the Rietveld method. Initial structure solutions yielded an unreasonable conformation, and an unacceptable refinement. Quantum chemical geometry optimizations were used to identify the correct conformation. Guaifenesin crystallizes in the orthorhombic space group P212121 (#19), with a=7.657 05(7), b=25.670 20(24), c=4.979 66(4) Å, V=978.79(2) Å3, and Z=4. Both hydroxyl groups act as hydrogen bond donors and acceptors, resulting in the formation of a two-dimensional network of strong hydrogen bonds in the ac plane. The solid state conformation is ∼4 kcal/mol higher in energy than the minimum-energy conformation of an isolated molecule, but the formation of the hydrogen bonds results in an energy gain of ∼100 kcal/mol. Knowledge of the crystal structure permits quantitative phase analysis of guaifenesin-containing pharmaceuticals (such as Duratuss GP 120-1200) by the Rietveld method.

The crystal structure of γ-Mo4O11 was obtained at room temperature (296 K) by Rietveld analysis with X-ray powder diffraction data. The crystal belongs to orthorhombic system, space group: Pna21, Z=4, Mr=559.753 (Atomic weights 1977), Dx=4.1228 g/cm3, F(000)=1024.0, μ=451.293 cm−1 (Int. Tab. Vol. C, Table 4.2.4.2, p. 193, λ=1.540 60 Å), a=24.4756(5) Å, b=6.7516(1) Å, c=5.4572(1) Å, and V=901.80(3) Å3. The structure was refined to Rwp=5.60%, Rp=4.27%, Rb=3.36%, and Rf=2.74% for 65 parameters with 3541 step intensities and 3055 peaks. Goodness of the fit S=3.35.

Quantisation of low-quartz in crystalline mixtures has been performed by X-ray powder diffractometry (XRPD) for many years. Conventional methodology, using discrete-peak integrated intensities, is frequently performed employing calibrations prepared with natural low-quartz specimens. Previous research showed that from a conventional XRPD study of low-quartz specimens, the amorphous content of a suite of natural low-quartz specimens ranged from 1% to 28%. That study thereby underlined the importance in XRPD calibration of characterising the amorphous content (or its complementary quantity “weight fraction of crystalline material, WCFM” employed here). This paper describes an application of pattern-fitting Rietveld analysis for characterising the WCFM in a suite of low-quartz specimens. The results gave WCFM values ranging from 0.91 (esd, σ= 0.02) to 1.00(0.02) for six specimens for which the SiO2chemical content ≥ 99.5%.

The structural evolution of the “zero-strain” Li4Ti5O12 anode within a functioning Li-ion battery during charge–discharge cycling was studied using in situ neutron powder-diffraction, allowing correlation of the anode structure to the measured charge–discharge profile. While the overall lattice response controls the “zero-strain” property, the oxygen atom is the only variable in the atomic structure and responds to the oxidation state of the titanium, resulting in distortion of the TiO6 octahedron and contributing to the anode's stability upon lithiation/delithiation. Interestingly, the trend of the octahedral distortion on charge–discharge does not reflect that of the lattice parameter, with the latter thought to be influenced by the interplay of lithium location and quantity. Here we report the details of the TiO6 octahedral distortion in terms of the O–Ti–O bond angle that ranges from 83.7(3)° to 85.4(5)°.

X-ray powder diffraction data, unit-cell parameters, and space group for meloxicam, C14H13N3O4S2, are reported [a = 6.997(2) Å, b = 8.113(2) Å, c = 13.604(4) Å, α = 85.774(2)°, β = 88.311(1)°, γ = 74.994(1)°, unit-cell volume V = 743.821 Å3, Z = 2, and space group P-1]. All measured lines were indexed, and no detectable impurity was observed.

An algorithm has been derived, forming the basis of a computer program called BBCCURV, which calculates a Bragg-Brentano X-ray diffractometer intensity correction curve (intensity correction factor Kivs. 2θi) given the diffractometer and sample dimensions, and the effective (not theoretical) linear absorption coefficient of the sample. Use of this calibration curve gives a set of intensity data free from aberrations, which are caused mainly by sample transparency, curvature of the diffraction cones passing through the receiving slit and possible beam overflow past the specimen at low angles.

The algorithm was confirmed with a full-profile Rietveld refinement of Bragg-Brentano X-ray diffraction data from a H+-ZSM5 zeolite sample. On introducing a BBCCURV correction curve, the profile R-factor over the pattern points dropped from 30.8% to 16.5%, a significantly better fit when the data were corrected with a BBCCURV curve.

BBCCURV intensity calibration curves from LiF (μ= 1.5 mm−1) through zeolites, clays, ZnO, rutile, Pb(NO3)2and finally solid metal (μ= 1000 mm−1) (CoKα) indicate upward revision of the measured diffractometer intensities by factors of between 2 and 10 at 2θ= 5° for these sample types, normalised to a correction factor of 1.0 at 2θ= 44°. Corrections of this magnitude to Bragg-Brentano data are thus significant in full-profile structure refinement and quantitative analysis with Bragg-Brentano data. Use of a variable divergence slit (VDS) is not appropriate in full-profile refinements as the intensity aberrations are magnified, and conversion from VDS data to aberration-free data is sample- and transparency-dependent, and not the simple area (sinθ)−1function generally assumed. Use of a fixed divergence slit with a BBCCURV-type calibration is recommended.

The crystal structure of the layered cadmium hydroxide sulfate Cd4SO4(OH)6.1.5H2O has been solved from X-ray powder diffraction data. The compound crystallizes with hexagonal symmetry, a=9.145(1) Å, c=15.099(3) Å, V=1093.5 Å3, Z=4, space group P63. Due to the unusual environment of one cadmium atom and to the fact that a suitable thin tabular crystal could be found later, a single-crystal X-ray diffraction experiment was also carried out. In both cases the structure was solved applying direct-methods. The refinements converged to the residual factors Rwp=0.152 and RF=0.059 from the powder data and R1=0.058 and wR=0.165 for the single crystal data case. The structure is built from brucite-type layers based on CdO6 octahedra, in which one-seventh of the octahedral sites are empty. Directly above and below these empty sites, two additional octahedrically coordinated Cd atoms are located. The crystal chemistry of the cadmium hydroxide sulfate family is discussed.

Estimation of reference intensity ratios (ki or RIR) can be made on the basis of an atomic scattering function. Tests of regression equations for 50 compounds that predict an approximate reference intensity ratio from the easily computed scattering function have shown usefulness in multicomponent semiquantitative X-ray diffraction analysis. The method is best applied whenever only one or two minor components of a multicomponent sample have no readily measurable or calculable ki values and must be estimated. Where the difference between observed and predicted constants is large, these tests show that the ratios of true- to test-weight fractions are proportional to the corresponding ki ratios. The largest absolute errors occur whenever the ki must be predicted for components with medium weight fraction values. Estimation of ki for components of less than 10 weight percent results in only small errors in both predicted component and the other components of the sample. Where more than two components require predicted ki in a given sample, unacceptable errors for all components may result.

A software for the calculation of diffraction elastic constants (DEC) for materials both with and without preferred orientation was developed. All grain-interaction models that can use the crystallite orientation distribution function (ODF) are incorporated, including Kröner, Hill, inverse Kröner, and Reuss. The functions of the software include: reading the ODF in common textual formats, pole figure calculation, calculation of DEC for different (hkl,φ,ψ), calculation of anisotropic bulk constants from the ODF, calculation of macro-stress from lattice strain and vice versa, as well as mixture ratios of (hkl) of overlapped reflections in textured materials.

The fundamental parameter method for quantitative analysis of composite elements has been a powerful technique for x-ray spectrochemical analysis in which the x-ray intensity and spectral distribution from x-ray spectrographic tubes are the moste ssential factors in the calculating process based on x- ray physics.

This work introduces a new simple approach to determine experimental X-ray elastic constants (XECs) of thin films by coupling the sin2ψ method and the substrate curvature technique. The approach is demonstrated on polycrystalline Cu thin films with the thickness 200, 800, and 2400 nm deposited on Si(100) substrates. Applying synchrotron radiation, the elastic strains in the films are determined using sin2ψ method while the macroscopic stresses are assessed by measuring the substrate curvature. The stresses are calculated using the Stoney formula from the radius of substrate curvature determined by the rocking curve measurement of substrate 400 reflection at different sample positions. Results show that the magnitude of the macroscopic stress in the films is proportional to the magnitude of the slope in the sin2ψ plots. On the basis of this observation, XECs of the films were calculated showing no dependence on the film thickness. The characterization of the samples was performed at the synchrotron source Hasylab.

The crystal structure of monoclinic CuF2 has been refined by the Rietveld method from X-ray powder diffraction data. The structure is monoclinic, space group P21/n, a = 3.2973(2), b = 4.5624(3), c = 4.6157(3) Å, β = 83.293(3)°, V = 68.96(2) Å3, with Cu+2 at (0,0,0) and F−1 at (−0.04176(68), 0.29410(35), 0.29410(35)). Final RB = 0.97%, RP = 1.99%, Rwp = 2.32%, RWP(expected) = 1.46%. The structure has a rutile-type arrangement, but with a monoclinic distortion that produces a highly distorted octahedral coordination around the Cu2+ ion with equatorial and apical Cu-F distances of 1.92 and 2.32 Å respectively.

Advances in X-ray texture solutions require new methods and descriptions for the texture analysis process, e.g., when using general area detector diffraction systems. A new method is presented that defines a general pole figure resolution and provides the possibility to optimize strategies for efficient pole figure data collection. Application of the new method improves resolution and (!) speed. New software enables simultaneous monitoring of pole and detector space. This allows a fundamentally better understanding of the collected information, e.g., in situations where peaks overlap or high backgrounds compromise data quality.

The mathematical relationships are developed which are pertinent to the quantitative analysis of powder mixtures for the case of diffraction from the surface of a flat powder specimen. These formulas relate the diffracted intensity to the absorptive properties of the sample. Three important cases are treated: (1) Mixture of n components; absorbing powder of the unknown equal to that of the matrix; concentration proportional to intensity. Direct analysis is permitted. (2) Binary mixture; absorbing powder of the unknown not equal to that of the diluent; concentration not proportional to intensity. Direct analysis is possible by means of calibration curves prepared from synthetic mixtures. (3) Mixture of n components; absorbing power of the unknown not equal to that of the matrix; general case. Analysis is accomplished by the addition of an internal standard. Concentration is proportional to the ratio of the intensity of a selected reflection from the unknown to the intensity of a reflection from the internal standard.