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.

The crystal structures of Mek[Fe(CN)6];l·mH2O where Me = Cu, Ni and Co, have been refined from X-ray (CuKa) powder diffraction data by means of Rietveld analyses in space group . The Fe and Me ions are octahedrally coordinated by C and N atoms respectively, forming three-dimensional bimetallic networks with the CN-groups as bridging ligands. The Me(l) sites (k = 2, l=1) and the Fe sites (k = 3, l = 2) are partially occupied. Water oxygens were placed in alternative, empty metal sites.

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.

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.

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.

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.

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.

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.

A new and improved sample holder for use with powder X-ray diffractometry has been developed. This holder is made from a semiconductor grade silicon single crystal cut perpendicular to the [911] axis, i.e., Si (911). This crystal meets most of the basic requirements of an ideal zero background plate, with practically no interference lines. The pattern obtained, by using this crystal as background plate, is very clean, and even very low-intensity Bragg reflections of samples can be detected easily.

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.

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.

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.

Particle statistics in quantitative X-ray diffractometry relates to the number of particles (crystallites) contributing to the diffracted intensity for a given line. Variations in line intensity between replicate preparations of the same sample arise from statistical variations in the number of diffracting particles. The uncertainty in line intensity, and hence in quantitative estimates of analyte concentration, is termed the particle statistics error. A theoretical estimate of the error for stationary samples qives σPS=ξ[μ*〈v〉/c]1/2, where μ* is the mass absorption coefficient of the mixture, and 〈v〉 and c are the mean particle volume and mass concentration respectively of the analyte. The factor ξ is a function mainly of diffractometer geometry, but also contains contributions from rocking angle and reflection multiplicity. For measurements of the (112) quartz line with a Philips PW1050 vertical goniometer with 2o divergence slit and 0.3 mm receiving slit, ξ was calculated to be 116 g1/2 cm−5/2 for stationary samples. Three close-cut size fractions of quartz were prepared at various concentrations in a calcium carbonate matrix. Replicate preparations were measured and the standard deviation obtained as a function of particle volume and concentration. After correction for other contributing errors, including counting statistics and thermal fluctuations, the experimental value ξ=122±10 g1/2 cm−5/2 was obtained. The effect of sample spinning is considered briefly and predicted to reduce σPS by a factor of about 5. Experimentally, a reduction in σPS of about this order is observed, but the effect is rather variable.

The structure of the oxyphosphate Li0.50Ni0.25TiO(PO4) has been determined from conventional X-ray and neutron powder diffraction data. The parameters of the monoclinic cell (space group P21/c, Z=4), obtained from X-ray results, are: a=6.3954(6) Å, b=7.2599(6) Å, c=7.3700(5) Å, and β=90.266(6)°; those resulting from neutron study are: a=6.3906(7) Å, b=7.2568(7) Å, c=7.3673(9) Å, and β=90.234(7)°. Refinement by the Rietveld method using whole profile, leads to satisfactory reliability factors: cRwp=0.128, cRp=0.100, and RB=0.038 for X-ray and cRwp=0.110, cRp=0.120, and RB=0.060 for neutrons. The structure of Li0.50Ni0.25TiO(PO4) can be described as a TiOPO4 framework constituted by chains of tilted corner-sharing TiO6 octahedra running parallel to the c axis and cross linked by phosphate tetrahedra. In this framework, there are octahedral cavities occupied by Li and Ni atoms: Li occupies the totality of the 2a sites and Ni occupies statistically half of the 2b sites. Ti atoms are displaced from the center of octahedra units in alternating long (2.242 Å) and short (1.711 Å) Ti–O bonds along chains.

X-ray diffraction pattern from cotton fiber (dch32) grown in the Karnataka state of India has been recorded. Fiber was found to contain 17 Bragg reflections, of which 11 are broadened because of crystal size and intrinsic strain influences. Contributions to integrated intensities from intrinsic strain in the fiber have been estimated using line profile analysis. A molecular model was first constructed with standard bond lengths and angles using helical symmetry and layer-line spacings observed in the X-ray pattern. The model was then refined against observed X-ray data using the linked atom least squares (LALS) method. The refinement has been done with and without the intrinsic strain correction to find the extent of structural changes. These changes have been quantified in terms of bond angles, bond lengths, and torsion angles. Young’s modulus has been estimated for these fibers using the results of line profile analysis, and a broad agreement with the reported physical measurements has been obtained.

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.

In situ laboratory-based and in situ synchrotron X-ray diffraction techniques were employed to study quantitatively the strain-induced austenite-to-martensite (A–M) transformation in thermally cycled (TC) superelastic NiTi alloys. The propagation of the A–M interfaces and the evolution of the microstructure were traced during uniaxial tensile loading. It was shown that the TC material exhibits localized transformation via the propagation of transformation bands. The amount of the martensite phase depends approximately linearly on the applied strain. Analysis of the broadening of the austenite diffraction lines indicates the presence of highly deformed austenite grains within the transformation bands. Analysis of the austenite diffraction-line shifts indicates that the overall lattice strain in the (retained) austenite in the transformation bands differs from that of the austenite in the adjacent untransformed regions.

Advances in instrumentation, software applications, and database content have all contributed to improvements in pharmaceutical analyses by powder diffraction methods in the 21st century. When compared to the globally harmonized United States Pharmacopeia General Chapter <941>, “Characterization of Crystalline and Partially Crystalline Solids by X-ray Powder Diffraction”, many historic problems in pharmaceutical analysis have been addressed by combinations of improved methods and instrumentation. Major changes in the last 20 years include (i) a dramatic lowering in detection capability and detection limits, (ii) enhanced capabilities for dynamic measurements such as in situ analyses under a variety of conditions, and (iii) the ability to identify and characterize nanomaterials, non-crystalline, and amorphous materials by both coherent and incoherent scattering profiles.