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.

Cu-paddle-wheel-based Cu3(BTC)2 (nicknamed Cu-BTC, where BTC ≡ benzene 1,3,5-tricarboxylate) is a metal organic framework (MOF) compound that adopts a zeolite-like topology. We have determined the pore-size distribution using the Gelb and Gubbins technique, the microstructure using small-angle neutron scattering and (ultra) small-angle X-ray scattering (USAXS\SAXS) techniques, and X-ray powder diffraction reference patterns for both dehydrated d-Cu-BTC [Cu3(C9H3O6)2] and hydrated h-Cu-BTC [Cu3(C9H3O6)2(H2O)6.96] using the Rietveld refinement technique. Both samples were confirmed to be cubic Fm $\bar 3$ m (no. 225), with lattice parameters of a = 26.279 19(3) Å, V = 18 148.31(6) Å3 for d-Cu-BTC, and a = 26.3103(11) Å, and V = 18 213(2) Å3 for h-Cu-BTC. The structure of d-Cu-BTC contains three main pores of which the diameters are approximately, in decreasing order, 12.6, 10.6, and 5.0 Å. The free volume for d-Cu-BTC is approximately (71.85 ± 0.05)% of the total volume and is reduced to approximately (61.33 ± 0.03)% for the h-Cu-BTC structure. The d-Cu-BTC phase undergoes microstructural changes when exposed to moisture in air. The reference X-ray powder patterns for these two materials have been determined for inclusion in the Powder Diffraction File.

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.

This is a second and considerably expanded edition of the RIR table. We are pleased that considerable interest is now being generated in the RIR table; several contributors have provided measured data for this second edition. We have also added many entries of common minerals and simple compounds from the JCPDS data base and will continue to add more from this source with each succeeding table published. In this regard where we receive requests for a particular class of RIR's (alloys, or rare earth oxides, for examples) we can give higher priority to extracting these values from the JCPDS data base.

The reader should refer to the text explanation of the first published table in Vol. 3, No. 4 of this journal. In the first text two important errors are noted here; Equation (3) should have read RIRcorr = RIRobs/Wj; and the second sample preparation category of section 4 Specific Parameters should read “(w) Methods including well mounts with side or back loading or similar process”.

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 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.

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.

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.

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.

The analysis of thin insulating films occurring in various stages of the manufacture of integrated circuits has in the past been difficult, if not impossible. Their dimensions usually preclude analysis by conventional chemical techniques, hence very little is known concerning their relative stoichiometrics. However, by microprobe analysis, films as thin as 540 Å (∼18μg/cm2) have been successfully analyzed. In general, two different approaches are taken, depending on the film thickness. Usually, films thicker than 2500 Å (∼50μg/cm2) are analyzed by conventional microprobe techniques. A computer program, called MAGIC, has been written, which converts the raw X-ray intensities to chemical composition. All data are corrected for dead time, background, absorption, atomic number effects, and fluorescence by characteristic radiation, if required. A minimum of input is required, only the chemical symbols. X-ray lines employed, and the accelerating voltage being necessary in addition to the raw X-ray intensities. All constants such as atomic weights, critical excitation potentials, X-ray wavelengths, and absorption coefficients are stored or calculated internally, which reduces the errors and time associated with looking up and key-punching these values. New fluorescent yields are used for K and L radiation. No fluorescence correction is made for M radiation. The use of this correction program generally gives results, accurate to about 2 to 4%, relative to the amount present. For films thinner than 2500 Å, a new model is proposed which allows the X-ray spectra from the film and substrate to be unfolded to give the composition of the film only. To accomplish this, the atomic number correction of Duncumb and deCasa employed in MAGIC has been used in conjunction with a mean electron energy concept. Results obtained to date through the use of this model have been surprisingly good, being of the order of 5% relative to the amount present. Potential errors and uncertainties are discussed, and results given which illustrate the accuracy of the two 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.

A pragmatic, easily applied theory of the extended X-ray absorption fine structure found on the high-energy side of absorption edges is developed. This simple model can be successfully applied to determinations of interatomic distances, and it accounts for differences in Kronig structure on different absorption edges in the same material. Quantitative agreement with experimental data is good.

A straightforward intuitive user-friendly compact graphical interface, PreDICT (Premier DICVOL Tool) has been developed to take full advantage of the new capabilities of the most recent version of the DICVOL14 Indexing Software. The latter, an updated version of DICVOL04, includes optimizations, e.g. for monoclinic and triclinic cases, a detailed review of the input data from the indexing solutions, cell centering tests, as well as the handling of a moderate number of impurity peaks. Among the most salient features of PreDICT, one can mention the ability (1) to use 2θ non-equistepped input 1D X-ray powder diffraction patterns as can be obtained from 2D detectors, (2) to strip laboratory data from its Kα2 contribution when present, (3) to generate 2θ equistepped output 1D X-ray powder diffraction patterns in both the “.XY” and “.GSA” formats. In addition, PreDICT allows for the following features: (1) full access to the native DICVOL14 input/output ASCII file system is retained, (2) for any selection of a DICVOL14 suggested unit cell, all predicted Bragg peaks up to a certain 2θMAX value are clearly displayed and indicated, thereby emphasizing the contribution of the unaccounted peaks (if any) to the 1D X-ray powder diffraction pattern under current investigation.

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.

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 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.

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.