Total scattering data of nanocrystalline gahnite (ZnAl2O4, 2–3 nm) have been collected with three of the most commonly used instruments: (i) ID31 high-resolution diffractometer at the European Synchrotron Radiation Facility (ESRF) (Q max = 22 Å−1); (ii) ID11 high-energy beamline at the ESRF (Q max = 26.6 Å−1); and (iii) Empyrean laboratory diffractometer by PANalytical with molybdenum anode X-ray tube (Q max = 17.1 Å−1). Pair distribution functions (PDFs) for each instrument data-set have been obtained, changing some of the parameters, by PDFgetX3 software, with the aim of testing the software in the treatment of different total scattering data. The material under analysis has been chosen for its nanometric (and possibly disordered) nature, to give rise to a challenge for all the diffractometers involved. None of the latter should have a clear advantage. The PDF and F(Q) functions have been visually compared, and then the three PDF sets have been used for refinements by means of PDFgui suite. All the refinements have been made exactly in the same way for the sake of a fair comparison. Small differences could be observed in the experimental PDFs and the derived results, but none of them seemed to be significant.

Standard Reference Materials (SRMs) for determining instrumental line profiles should not exhibit measurable broadening from structural imperfections, but owing the effects of sample transparency and other geometrical effects, the quality of possible SRMs cannot necessarily be assessed satisfactorily with data from a conventional divergent-beam diffractometer. The problem of transparency can be avoided if parallel beam optics is used, as for instance on a synchrotron radiation powder diffraction station employing Parrish (Soller-type receiving slit assembly) geometry. Data from such a configuration are used to compare three SRMs commonly used in line-profile analysis.

The crystal structures of two manganese hexacyanometallates(II), Mn2[Fe(CN)6].8H2O and Mn2[Os(CN)6].8H2O, were refined from X-ray powder diffraction data using the Rietveld method, with the reported structure for Mn2[Ru(CN)6].8H2O used as a structural model. These compounds are isomorphous and crystallize in the monoclinic space group P21/n. Their crystallization water is not firmly bound and can be removed without disrupting the M–C≡N–Mn network. In the dehydrated complexes, the outer cation (Mn) remains linked to only three N atoms from CN ligands while the inner cation (Fe,Os) preserves its coordination sphere. The IR, Raman, and Mössbauer spectra for the hydrated and anhydrous forms are explained based on the refined structures.

Diffraction peak broadening analyses were carried out on diffraction profiles of several reflections from hot-pressed α-Al2O3 containing 29, 18 and 10 volume % β-SiC whiskers. The data were analyzed and compared using four different integral breadth methods for microstrain and crystalline size. All four methods gave comparable results, within an order of magnitude, for the microstrains in each phase: (2-15 × 10−4 for the matrix and (6-19 × 10−4 for the whiskers). Microstrains in both matrix and whiskers decreased with decreasing volume % of whiskers for all four methods. Trends in the crystallite size were less consistent but for the matgrix, an incrfease from ∼665 to 1565Å was found with decreasing whisker content using DeKeijser's method.

XRD analysis of plasma-vapor-deposited ErT2 films during aging (T decay to 3He) reveals an hkl-dependent unit-cell expansion in which (200) grains expand out-of-plane as much as 0.01 Å more than (111) out-of-plane grains. Texture analysis of an aged ErT2 film reveals a bimodal (111)/(200) out-of-plane preferred orientation. sin2 ψ analysis reveals significant in-plane macro-strain due to 3He bubble formation/growth. The mechanistic origins regarding these observations are also discussed.

The object of the Rietveld method is to produce refined values of crystal structural parameters from powder diffraction data. Many materials of great interest can not be made available for study in single crystal form. This may be because it is not possible to prepare a single-crystal form at all (e.g., human tooth enamel) or because the single-crystal form differs from the polycrystalline form with the properties of interest (e.g., catalysts). Thus, our basic understanding of the atomic scale mechanisms is limited on the structural side by the information that can be deduced from powder diffraction patterns. (Only diffraction and EXAFS are direct probes of the spatial arrangements of atoms.) The Rietveld method has greatly extended the amount of structural detail that we can obtain routinely from powder diffraction patterns. In this method, structural parameters such as atom coordinate, thermal motion, and site occupancy parameters are adjusted in a least-squares refinement procedure until the best fit is obtained between entire calculated and observed powder diffraction patterns, as a whole.

For research facilities with access to synchrotron X-ray sources, X-ray absorption microtomography (XMT) has evolved from an experimental imaging method to a specialized, if not yet routine, microscopy for imaging the three-dimensional (3D) distribution of linear attenuation coefficients and, in some cases, elemental concentration with micron spatial resolution. Recent advances in source and detector design have produced conventional X-ray source instruments with comparable spatial resolution but with lower throughput and without element specific imaging. Both classes of instrument produce 3D images for analysis. We discuss an integrated approach for the implementation of analytical XMT to support basic research into the structure-property relationships of a variety of materials. The essential components include instrumentation for collecting quantitative 3D images, a 3D image processing environment to address questions as to the quantity, composition, geometry, and relationships among the features in one or more images, and visualization to provide insight and communicate results. We give examples of image analysis of resolved and unresolved pore spaces of sandstones.

Powder X-ray diffraction (XRD) data were collected for La0.65Sr0.35MnO3 prepared through an alternative method from a stoichiometric mixture of Mn2O3, La2O3, and SrO2, fired at 1300 °C for 16 h. XRD analysis using the Rietveld method was carried out and it was found that manganite has rhombohedral symmetry (space group R3c). The lattice parameters are found to be a=5.5032 Å and c=13.3674 Å. The bond valence computation indicates that the initial inclusion of Sr occurs at higher temperature.

An analysis of the microstructure of nanocrystalline yttrium oxide produced by thermal decomposition of a double oxalate yttrium and ammonium, at temperatures in the range 600 °C to 900 °C, is described. The study is based on line broadening analysis carried out with the (Voigt/Langford) integral breadth and Fourier methods combined with the pattern decomposition technique. Due to the line overlap arising from the density of diffraction lines, the whole pattern refinement method (pattern matching and Rietveld approaches) is also applied. No marked line broadening anisotropy is observed in the patterns. It is shown that for the two samples prepared at the highest temperatures the results are similar whatever the method used and the material can be considered as strain free. For the two lowest temperatures only the whole pattern refinement method is applied. The results suggest that a small amount of lattice microdistortion is present in these two last samples. It is shown that the crystallite growth varies exponentially with temperature. The results obtained from line broadening analysis are compared to those observed with scanning electron microscopy, from which a good accordance is noted between the two techniques.

The capacity of goethite for CdII substitution has been explored in a series of synthetic samples prepared from FeIII and CdII nitrate solutions aged 21 days in alkaline media. The total metal content ([Fe]+[Cd]) was 0.071 M in all preparations. The samples have been characterized by chemical and X-ray diffraction analysis; the morphology of the solids is described. The cell parameters for all samples were obtained by the Rietveld fits to the X-ray diffraction data. Refined structures show that for samples prepared at the final molar ratio μCd≤5.50 (expressed as μCd=100×[Cd]/[Cd]+[Fe]), a (Cd, Fe)-goethite is the only crystalline product. In these samples, the unit cell parameters increased as a function of Cd concentration, indicating Cd incorporation in the structural frame. At the preparative ratio, μCd=7.03, the incorporation of Cd in the goethite structure is drastically reduced and a probable Cd-substituted hematite is formed together with the Fe,Cd-goethite.

The objectives of this paper are: 1. to up-date the manual search system and index book described in 1936 and 1938; 2. to introduce a “work form” which serves to guide the analyst through the procedural steps involved in using the manual search index book and 3. to review briefly the literature on manual search/match systems.

Two of the basic features of the 1936 design of the search index book were first, to divide the “d” range into arbitrarily sized “groups” and “subgroups” rather than using a scale of continuously decreasing “d” values, and second, to use the “d” values of the strongest lines of the diffraction pattern in order of decreasing intensity in making the entries of the standard patterns in the search index book. These two features are still the basis of the design of the 1986 Hanawalt Search Manual published by the JCPD S International Centre for Diffraction Data.

The original use of the search index book at Dow Chemical was to lead the analyst to corresponding patterns among the thousands of Debye films which had been produced and placed on file. The “d” values and intensities of only the three or four strongest lines of the pattern were measured. Comparisons and indentifications were then made visually simply by holding the concerned films together in juxtaposition. Unfortunately, attempts to reproduce usable copies of such Debye films for general reference have not been satisfactory. Therefore, for general usage the diffraction data carried by the film negative or also the data from a diffractometer trace are recorded using the numerical values of the “d” spacings and intensities. These tables of numerical data are then used to represent the diffraction patterns. The search index book for general usage must therefore deal entirely with these numerical values.

An interlaboratory study (ILS, round robin) was conducted to assess the accuracy and precision of the phase quantification of calcium phosphate (CaP) bioceramics by X-ray diffraction (XRD) and Rietveld refinement. For that purpose, a mixture of hydroxyapatite and β-tricalcium phosphate, two CaP phases commonly used in synthetic bone graft substitutes, was prepared and sent to 12 laboratories for XRD analysis. Results from 26 different instruments were received and evaluated statistically according to ASTM E691 – 13. The statistical analysis revealed that the reproducibility standard deviation of phase quantities was approximately two times greater than the repeatability standard deviation, which is obtained by repeating the analysis on a single instrument configuration multiple times. The 95% reproducibility limit for phase quantities was R = ±1.67 wt%. The study also demonstrated that several participants overinterpreted their data in an attempt to refine crystallite sizes of the minor phase.

A novel borate compound Ba3ScB9O18 has been synthesized by solid-state reaction and its structure has been determined and refined from powder X-ray diffraction data. This compound crystallizes in a hexagonal cell (space group P63/m) with lattice parameters a=7.1360(4) Å and c=16.5420(9) Å, and each unit cell contains two formulas. Its crystal structure is made up of planar B3O6 groups parallel to each other along the [001] direction, regular ScO6 octahedra, irregular BaO6 hexagons, and BaO9 polyhedra to form an analogue structure of Ba3YB9O18. DTA and TGA curves for Ba3ScB9O18 show that it is a chemically stable and congruent melting compound. Luminescence properties for Ba3ScB9O18 were investigated using fluorescence spectroscopy and X-ray excited luminescence measurements. Its emission spectrum upon UV excitation (330 nm) has exhibited a prominent blue-green emission band at about 490 nm, and its XEL spectra show an intense emission band in the range of 360 to 500 nm with peak center at 400 nm. The light yield of Ba3ScB9O18 powders is about 23% as large as that of BGO powders under the same measurement conditions. There seems to be a certain relationship between the scintillation properties and the structural features of Ba3ScB9O18.

Synchrotron X rays were used to perform nondestructive transmission diffraction and fluorescence experiments on a group of 24 European and Islamic astrolabes dated between 1350–1720 A.D. in order to determine their compositions. A group of six astrolabes produced in Lahore between 1601–1662 A.D. were found to contain a mixed α+β brass microstructure, proving that the brass was produced by a comelting technique rather than the traditional cementation process. The results also show evidence of dezincification, attributed to heavy annealing of the brass during astrolabe manufacture. This effect was so severe that an accurate analysis of the bulk Zn composition could not be determined from the fluorescence results alone; transmission X-ray diffraction gives a more accurate measurement of the bulk Zn composition.

Recent developments in the Rietveld method for the analysis of powder diffraction data have seen the method evolve from its original purpose of crystal structure refinement to include the determination of phase abundance in polycrystalline mixtures and the estimation of crystal size and strain parameters. However, the Rietveld method is not easy to use and may deter many powder diffractionists, who are not interested in structure refinement per se, from using the method in its non-structural applications.

In order to overcome the difficulties in using the Rietveld method, a program, QPDA (for Quantitative Powder Diffraction Analysis), has been written that sets the conditions necessary for a single or multi-phase refinement, runs the Rietveld program and extracts phase abundance and size/strain information from the refined parameters. The program comprises a user-friendly, default-driven system of subroutines, written initially in VAX Fortran, and operates from a database of inorganic materials frequently encountered in a wide range of minerals and materials science industries.

Ternary systems CuO-M2O3-TO2 with T = Si, Ge and M3+ = Al, Ga, Fe, Cr, Bi and Y were investigated at 1000°C. Ternary compounds were found only for M3+ = Y. CuY2Ge2O8 is monoclinic with a = 9.477 Å, b = 15.005 Å, c = 8.030 Å and β = 147.50°; CuY2 Si4 O12 is monoclinic with a = 7.052 Å, b = 14.283 Å, c = 4.738 Å and β = 103.32°; CuY2Ge4O12 is triclinic with a = 7.185 Å, b = 7.949 Å, c = 4.910 Å, α = 86.83°, β = 102.70° and γ = 113.84°. The last two structures are closely related. The binary double oxide series Cu2Ln2O5 was reinvestigated.

Since Boeke's finding of a reversible phase transition of calcite (calcium carbonate, CaCO3) at elevated temperatures [Boeke, H. E. (1912). Neues Jahrb. Mineral. 1, 91–121], and following W. L. Bragg's determination of the structure of the room-temperature Phase I [Bragg, W. L. (1914). Proc. R. Soc. Lond. A 89, 468–489.], the high-temperature Phase V of calcite has been an enduring mystery. Here, we summarize a paper on the structure of Phase V [Ishizawa, N., Setoguchi, H. and Yanagisawa, K. (2013). Sci. Rep. 3, 2832], as well as the intermediate Phase IV which exists between Phases I and V, and add new aspects. An in situ single-crystal X-ray diffraction study revealed that the I–IV and IV–V transitions occurred reversibly at approximately 985 and 1240 K, respectively, in a carbon dioxide atmosphere. Phase V was stable only over a narrow temperature range between 1240 and 1275 K. The crystal decomposed immediately at temperatures above 1275 K, leaving a nanoporous calcium oxide reaction product which retained the shape of the parent calcite crystal. The I–IV transition can be described as an orientational order/disorder transition of the carbonate group, occurring within the same space group $R\bar 3c$. In Phase V, the oxygen sublattice is melted. The joint-probability density function obtained from the anharmonic atomic displacement parameters of the oxygen atoms revealed that the oxygen triangles of the carbonate group in Phase V do not sit still at specified Wyckoff positions in the space group $R\bar 3m$, but are instead distributed with equal probability along the undulated circular orbital about the central carbon. The carbonate group in Phase V is no longer flat on the basal plane when the oxygen triangle comes to troughs or peaks in the undulated orbital, but is instead deformed like an umbrella. Assuming that the oxygen triangle migrates about carbon, the carbonate group should repeat the umbrella inversion in Phase V as a function of time. Finally, possible thermal decomposition mechanisms of calcite are briefly discussed.

Novel plate-stratiform nanostructured Bi12O17Cl2 was studied with its visible-light photocatalytic performance. The Bi12O17Cl2 photocatalyst synthesized by a solid-state reaction was constructed of dozens of primary nanosheets, which were stacked by a parallel array of ultrathin secondary nanosheets. The microstructure and crystal structure of Bi12O17Cl2 primary and secondary nanosheets were discovered by high-resolution transmission electron microscopy and selected-area electron diffraction analyses. Its absorption edge was determined as about 590 nm and the band gap energy was 2.1 eV. The Bi12O17Cl2 nanomaterial exhibited superior visible-light-responsive photocatalytic activity and confirmed successful photodegradation of methyl orange (MO) under visible-light irradiation. The degradation efficiency was up to 97% in 90 min. Furthermore, the Bi12O17Cl2 photocatalyst exhibited excellent photostability and high mineralization capacity for MO photodegradation reaction. The MO photodegradation process was dominated by the direct photocatalytic mechanism. The contribution from its morphology and microstructure to superior photocatalytic activity was discussed.

A technique and apparatus are described for obtaining the elastic constant E/(1 + v) in selected crystaliographic directions for the purpose of calibrating x-ray diffraction residual stress measurement methods. The preparation of a simple rectangular beam specimen with two active electrical resistance strain gages applied to the test surface is described. Samples are clamped in a diffractometer fixture designed to minimize displacement errors, and loaded in four-point bending to several stress levels below the proportional limit. A method is described for calculating E/(l + v) and an estimate of the experimental error.

Values of E/(l + v) obtained for several alloy-(hkl) combinations are presented. The results indicate that several alloys of current commercial interest exhibit significant elastic anisotropy.

Samples of single-phase Sr2FeMoO6 were successfully prepared by solid-state reaction with long sintering times. The crystal structures of the Sr2FeMoO6 samples were determined from X-ray powder diffraction data using the Rietveld refinement method. The structure results obtained by the Rietveld refinements show that an increase in the total sintering time of the solid-state reaction is an effective method to obtain single Sr2FeMoO6 phase and to improve the ordering of Fe and Mo cations (or reducing antisite defects) in the double-perovskite structure. The volume of the tetragonal unit cell of Sr2FeMoO6 contracts slightly after successive sintering treatments. The averaged Fe-O and Mo-O bond lengths as well as the tilt between the FeO6 and the MoO6 octahedra decrease with increasing total sintering time. Our results suggest that the detected subtle changes in crystal structure, such as bond lengths and bond angles between the Fe and Mo cations and oxygen, in the ordered double-perovskite structure may be responsible for the large effects on previously reported transport and magnetic properties of an oxide metal.