The following fifteen reference patterns of boride, silicide and oxide ceramics represent the first group of ceramic phases measured at the National Bureau of Standards under the project “High Quality Reference Patterns and Total Digital Powder Patterns of Technologically Important Ceramic Phases”. The support and interest of the JCPDS-ICDD in this project is gratefully acknowledged.

The general methods of producing these X-ray powder diffraction reference patterns are described in this journal, Vol. 1, No. 1, pg. 40(1986).

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.

A critical examination of the reference X-ray powder-diffraction patterns of the serpentine minerals in the Powder-Diffraction File (PDF) database has revealed an unsettling situation. Most of the patterns in, or previously in, the PDF database are inaccurate, misidentified, or of poor quality. The PDF database is not a dependable tool for identifying the serpentine minerals, and has not been since the mid-1960s. This has serious implications for studies on serpentine minerals that have depended on the PDF database, particularly those by nonmineralogists doing health and environmental studies of chrysotile asbestos. In the current PDF database, lizardite-1T, carlosturanite, some amesite, and possibly some antigorite (but with inappropriate polytype symbols) can be identified. Only one of the many multilayer lizardites can be identified. The current pattern for chrysotile-2Mc1 (clinochrysotile) is of reasonable quality, but not the best, however the earlier patterns still in the database are so problematic that any chrysotile-2Mc1 identification must be considered suspect. Chrysotile-2Oc1 (orthochrysotile), and any mixture of serpentines cannot be identified using the PDF database. Until the reference serpentine patterns are corrected the PDF database cannot be considered a reliable identification tool. High-quality powder-diffraction patterns of the serpentine minerals have been published and can be rapidly introduced into the PDF database.© 2000 International Centre for Diffraction Data.

Sauropod dinosaurs were typically one magnitude larger than any other living or extinct terrestrial animal. This sheer size of the sauropod leads to scale effects in their biology and physiology that still are inadequately understood. The only remnants of the sauropods are their fossilized bones. These fossilized bones have sustained burial for some hundred million years and thus may have experienced significant diagenetic changes. These diagenetic changes often do not affect bone preservation on the histological level, but may lead to significant alterations of the bone microstructure. Here the influence of diagenesis on the microstructure of fossilized sauropod bones using femur cross section of Brachiosaurus brancai that was excavated in the Tendaguru beds in Tanzania is investigated. The element distribution in this dinosaur bone is studied by a combination of micro-X-ray-fluorescence (μ-XRF) using synchrotron radiation and energy dispersive X-ray analyses (EDX) in the scanning electron microscope. These techniques reveal quantitative values of the element concentration at a macroscopic level combined with qualitative information at high spatial resolution of the distribution of Ca, Co, Cr, V, Pb, U, Sr, Y, and As in the fossil bones. This allows a differentiation between the remnants of the original bone apatite and pore filling minerals and also a visualization of damage, e.g., cracks introduced by diagenetic processes.

The General Structure Analysis System (GSAS-II) package provides materials and crystallographic analysis for all types of diffraction data. It was initially made available with very limited capabilities, but over much of the last decade the features have been expanded, so that GSAS-II is now a comprehensive tool for nearly all types of structural and materials characterization studies. The need to provide materials to teach use of GSAS-II, while the software has been undergoing constant revision and expansion, has required new approaches for documentation. This has included providing tutorials, as each major new capability has been added, and context-sensitive help for each section of the program. Comments in the code are also expanded into a software reference guide. Most recently, video versions of more than half of the tutorials were created and others were provided with animated graphics. All GSAS-II documentation is web-based.

Characterization of semi and noncrystalline materials, monitoring structural phase transitions in situ, and obtaining structural information together with spatial distribution of the investigated material are only a few applications that hugely benefitted from the combination of high-energy X-rays and modern algorithms for data processing. This work examines the possibility of advancing these applications by shortening the data acquisition and improving the data quality by using the new high-energy PILATUS3 CdTe detector.

A new classification of opals through X-ray powder diffraction (XRPD) methodology, by analysing 75 new samples of opal came from different worldwide areas, is introduced. A brief historical summary of the application of XRPD analysis on opals and the most important XRPD results reported in literature were compared with the newly obtained XRPD data. A simple method for the classification of opals on the basis of their degrees of structural order-disorder calculated from the diffraction data is proposed. In addition, a clear boundary, which has not been previously described by others in literature, related to the presence (or absence) of two-peak characteristic of the cristobalite phase is identified. This boundary allows for a discrimination of opals C from CT.

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.

Hydrothermally altered rocks hosting precious metal deposits frequently contain stacking disordered layer silicates. X-ray diffraction analysis using the Rietveld method can be used to determine mineral abundances in these rocks if suitable disorder models are applied. It is shown here that disorder models of kaolinite and pyrophyllite can be described by a recursive calculation of structure factors. This permits the physically sound refinement of real structure parameters of these disordered minerals and the determination of mineral abundances. Even mixtures containing two disordered Si–Al layer silicates can be quantified reliably. The developed disorder models can now be implemented in routine phase analysis, allowing the quantification of large numbers of samples to identify mineralogical gradients surrounding ore deposits.

Phase composition estimates by X-ray powder diffraction and Rietveld analysis are becoming more widely used in the cement industry. The ASTM C01.23 Compositional Analysis subcommittee developed test method C 1365, “Standard Test Method for Determination of the Proportion of Phases in Portland Cement and Portland-Cement Clinker Using X-Ray Powder Diffraction Analysis.” A round-robin analysis involving 11 laboratories was initiated to assess the precision and bias of this approach and to develop guidelines for Rietveld analysis of hydraulic cements. Four cements were prepared using NIST SRM clinkers spiked with known amounts of one or more of the following minerals: gypsum, bassanite, anhydrite, and calcite. Specimens were provided with instructions that laboratories analyze the whole cement, collect data in triplicate, and repack the specimen for each run. The results of the round robin were used to estimate interlaboratory and intralaboratory precision and bias of phase abundance determinations. The results show an improvement over previous cement round-robin studies utilizing traditional internal-standard-based, peak-area-measurement methods.

Literature data pertaining to the crystal chemistry, crystallography, and X-ray powder-diffraction properties of phases reported in the system BaO-CuOx are compiled. Reported phases include BaCuO2−2.12, BaCuO2.26−2.39, BaCuO2.5, Ba2CuO3+x, Ba2Cu3O5+x, BaCu2O2+x, Ba3Cu5O8, Ba3CuO4, BaCu3O4, Ba3Cu2O4+x, Ba5Cu3O6+x, and BaCu2O3. The existence of some of these phases, however, still has to be verified. Most of these compounds are nonstoichiometric in oxygen. Their oxygen content, and in some cases even their crystal structures, vary with oxygen partial pressure. There are also reported indications that the cations Ba and Cu are not stoichiometric in the cubic BaCuO2-type compounds.

Laboratory powder X-ray microdiffraction with a focusing monocapillary and linear multichannel detector was applied to phase identification in fragments of painting layers of art works, canvas and wall paintings, and polychromes on wood. This method is useful in materials research of painting layers with complex stratigraphy, and it is indispensable in distinguishing inorganic pigments of different natural provenance and revealing degradation products. The advantage of X-ray microdiffraction is its nondestructive nature and no need of sample pretreatment. Samples after microdiffraction can hence be used for other analyses or archived. Another advantage is the possibility to work with samples smaller than 1 mm, which is particularly important in the analysis of artworks where the sample amount or size is a serious limit of using the laboratory techniques of materials research. The X-ray equipment used is more economical and more easily accessible than other microdiffraction techniques and is, hence, suitable for routine analytical work.

Using X-ray grazing incidence diffraction (GID) it is possible to perform a nondestructive analysis of the heterogeneous stress field for different volumes below the surface of the sample. The stress can be measured at very small depths, of the order of a few μm. The penetration depth of radiation is almost constant in a wide 2θ range for a given incidence angle α. It can be easily changed by an appropriate selection of α angle (or also by using a different type of radiation). There are, however, some factors which have to be corrected in this technique. The most important is the refraction of X-ray wave: it changes the wavelength and direction of the beam. Both effects modify a pick position. A corresponding correction was calculated and tested on ferrite powder and on 316L austenite stainless steel sample.

Calcium hydroxyapatite (Ca10(PO4)6(OH)2) whiskers were prepared by using the technique of molten salt synthesis with the fluxing agent of potassium sulphate (K2SO4). A tentative x-ray diffraction (XRD) pattern was suggested for the produced whiskers. Phase purity, composition, and morphology of the whiskers were investigated by powder XRD, inductively coupled plasma-atomic emission spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy, respectively.

Verification tests of the forward modeling technique for near-field high energy X-ray diffraction microscopy are conducted using two simulated microstructures containing uniformly distributed orientations. Comparison between the simulated and reconstructed microstructures is examined with consideration to both crystallographic orientation and spatial geometric accuracy. To probe the dependence of results on experimental parameters, simulated data sets use two different detector configurations and different simulated experimental protocols; in each case, the parameters mimic the experimental geometry used at Advanced Photon Source beamline 1-ID. Results indicate that element orientations are distinguishable to less than 0.1°, while spatial geometric accuracy is limited by the detector resolution.

Standardized experimental and calculated X-ray powder diffraction data for a new synthetic zeolite, cesium titanium silicate, CsTiSi2O6.5, are reported. In addition, a structure model in space group Ia3d (230), which is isomorphous with the mineral pollucite (CsAlSi2O6·xH2O), is proposed for CsTiSi2O6.5. This structure model is the basis of the reported calculated X-ray powder diffraction data for CsTiSi2O6.5. The experimental pattern for CsTiSi2O6.5 shows this compound crystallizes in a body-centered cubic (BCC) unit cell with a=13.8423 (1) Å. The measured value of the reference intensity ratio (I/Ic) of CsTiSi2O6.5 is 2.37, while the contrasting calculated value of I/Ic is 4.45. The experimental density (Dm) of CsTiSi2O6.5 is 3.48±0.09 g/cm3, in agreement with the calculated density (Dx) of 3.42 g/cm3. Chemical analysis of CsTiSi2O6.5 by atomic absorption spectroscopy gives its composition as 54±2 wt% Cs; 23±2 wt% Ti; 23±2 wt% Si, which compares favorably with the theoretical composition of 56 wt% Cs; 20 wt% Ti; 24 wt% Si.

The X-Ray Powder Data File (XRPDF) enables one to identify the compounds in a sample. More often than not, however, a semi-quantitative analysis is wanted. Visual inspection of the pattern may give a vague impression of the composition, but the errors of such a result are usually not within reasonable limits. Clearly a less subjective and more accurate method is wanted. If the necessary data are printed on the cards, such a method will greatly enlarge the usefulness of the File.

Micro-X-ray fluorescence (μ-XRF) is a rapidly evolving analytical technique which allows visualising the trace level metal distributions within a specimen in an essentially nondestructive manner. At second generation synchrotron radiation sources, detection limits at the sub-parts per million level can be obtained with micrometer resolution, while at third generation sources the spatial resolution can be better than 100 nm. Consequently, the analysis of metals within biological systems using micro- and nano-X-ray fluorescence imaging is a quickly developing field of research. Since X-ray fluorescence is a scanning technique, the elemental distribution within the sample should not change during analysis. Biological samples pose challenges in this context due to their high water content. A dehydration procedure is commonly used for sample preparation enabling an analysis of the sample under ambient temperature conditions. Unfortunately, a potential change in elemental redistribution during the sample preparation is difficult to verify experimentally and therefore cannot be excluded completely. Creating a cryogenic sample environment allowing an analysis of the sample under cryogenic condition is an attractive alternative but not available on a routine basis. In this article, we make a comparison between the elemental distributions obtained by micro-SR-XRF within a chemically fixed and a cryogenically frozen Daphnia magna, a model organism to study the environmental impact of metals. In what follows, we explore the potential of a dual detector setup for investigating a full ecotoxicological experiment. Next to conventional 2D analysis, dual detector X-ray fluorescence cryotomography is illustrated and the potential of its coupling with laboratory absorption micro-CT for investigating the tissue-specific elemental distributions within this model organism is highlighted.

The crystal structures of four samples of anhydrite, CaSO4, were obtained by Rietveld refinements using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data and space group Amma. As an example, for one sample of anhydrite from Hants County, Nova Scotia, the unit-cell parameters are a = 7.00032(2), b = 6.99234(1), c = 6.24097(1) Å, and V = 305.487(1) Å3 with a > b. The eight-coordinated Ca atom has an average <Ca-O> distance of 2.4667(4) Å. The tetrahedral SO4 group has two independent S-O distances of 1.484(1) to O1 and 1.478(1) Å to O2 and an average <S-O> distance of 1.4810(5) Å. The three independent O-S-O angles [108.99(8) × 1, 110.38(3) × 4, 106.34(9)° × 1; average <O-S-O> [6] = 109.47(2)°] and S-O distances indicate that the geometry of the SO4 group is quite distorted in anhydrite. The four anhydrite samples have structural trends where the a, b, and c unit-cell parameters increase linearly with increasing unit-cell volume, V, and their average <Ca-O> and <S-O> distances are nearly constant. The grand mean <Ca-O> = 2.4660(2) Å, and grand mean <S-O> = 1.4848(3) Å, the latter is longer than 1.480(1) Å in celestite, SrSO4, as expected.

The hydration of ordinary Portland cements (OPC) was investigated with X-ray powder diffraction (XRPD) technique, mainly using synchrotron radiation. In situ experiments were performed during the first hours of hydration to study the evolution of the crystalline phases in the system. The hydration was carried out with pure water and in the presence of additives such as superplasticizers and setting accelerating agents. As soon as water is added to the cement, ettringite crystallizes. Its evolution appears to be very complex, and lattice parameters change as a function of setting time, indicating a possible chemical evolution of ettringite with time and as a function of pH. CSH (Ca-Si-hydrate) forms after a few hours from the beginning of hydration. CSH can be indirectly quantified and its evolution studied.