Substituting cations in materials with the formula Pb2B′B″O6 is more or less ordered on the B sites. High-quality single crystals of Pb2ScTaO6 (PST) and Pb(Sc0.5Nb0.5)O3 (PSN) were prepared from two thermal cycles. A stoichiometric mixture of the constituent oxides was prefired at up to 1000 °C, and then crystals were grown from a PbO–B2O3–PbF2 flux mixture, starting at a temperature of 1100 °C for PSN and 1200 °C for PST. At room temperature, X-ray examination showed that PSN had a perovskite structure with a cubic unit-cell and a refined parameter a = 4.080(1 ) Å, space group Pm3m and Z = 1, whereas PST formed a well-ordered superlattice with a = 8.136(1) Å, Z = 4 and space group Fm3m. In each case a fully indexed powder pattern is presented. The degree of order is estimated to be close to 80% for PST and less than 10% for PSN.

A series of five synthetic tetrahedrite-group minerals has been prepared and examined using powder X-ray diffraction in order to update current powder data and provide a validation test of cell dimension prediction equations. The tetrahedrites (nominally (Cu10X2)Sb4S13 with X = Zn, Cd, Mn, Hg and Fe) have the following properties: zincian tetrahedrite, a = 10.3833 (1) Å, Dx = 4.974 (1) g/cm3, F30 = 264 (0.004, 31), M20 = 279; cadmian tetrahedrite, a = 10.5066 (1) Å, Dx = 5.073 (1) g/cm3, F30 = 208 (0.004, 37), M20 = 249; manganoan tetrahedrite, a = 10.4384 (1) Å, Dx = 4.822 (1) g/cm3, F30 = 274 (0.003, 33), M20 = 302; mercurian tetrahedrite, a = 10.5071 (1) Å, Dx = 5.570 (1) g/cm3, F30 = 150 (0.006, 35), M20 = 156; ferroan tetrahedrite, a = 10.3630 (1) Å, Dx = 5.002 (1) g/cm3, F30 = 253 (0.004, 33), M20 = 281. The experimental unit cell dimensions obtained in this study are in excellent agreement with calculated values produced using regression equations developed previously.

Results on using X-ray optics with a monocapillary attached to a microfocus Mo X-ray tube for a high-intensity XRF analysis are reported. Au-coated glass monocapillaries with 400 and 700 μm inner diameters were used to obtain focused and intensive incident Mo X-rays for the measurements of XRF intensities from pure metal samples. Intensity enhancements obtained by using the Au-coated monocapillaries were found to be up to 1.5 times higher than those obtained by using similar inner diameter uncoated glass capillaries. The XRF intensity profiles were measured by the wire scanning method to investigate the reasons. The traces of the incident X-rays were calculated by taking into account of X-ray total reflection of the incident X-rays from the inner wall of the capillaries. The calculated XRF intensity profiles agree with those of the measured XRF intensity profiles. The observed enhancements in XRF intensity were the results of the incident X-rays emitted from the Mo X-ray tube being totally reflected on the inner wall of the Au-coated monocapillaries.

The fly ash Standard Reference Materials (SRMs) issued by the U.S. National Bureau of Standards have been studied by X-ray powder diffraction (XRD). Based on observations of large diffuse scattering maxima in their X-ray diffractograms, it was evident that all of the ashes had a high glass content. SRM 1633a and 2689, derived from the combustion of bituminous coal, contained different amounts of quartz, mullite, hematite and ferrite spinel (magnetite). SRM 2891, derived from subbituminous coal had quite a different chemical composition and a more complex crystalline phase assemblage, that included these four phases plus anhydrite, tricalcium aluminate, lime, periclase and minor phases. SRM 2690, also derived from subbituminous coal, had only quartz, mullite and ferrite spinel as detectable phases in its diffractogram. Analytical CaO is an important factor in determining the phase assemblage; SRM 2691 had 25.8 wt%, SRM-2690 had 8.0%, and the ash derived from bituminous coals had only 1.6-3.0%. The changing composition of the glass phases in the SRMs is detected in a shift in the position and shape of the diffuse scattering maximum in the diffractograms. Use of an internal intensity standard permitted quantitative comparisons of the relative amounts of crystalline phases among the four fly ash SRMs.

An X-ray powder diffraction analysis has been performed on several samples from the naturally occuring patina of the Statue of Liberty. This work, which was conducted as a service to the National Park Service as part of the restoration activities for the Statue, was performed to assess the impact of acid deposition on the phase composition of the patina. Samples of the patina that were obtained from various locations on the copper skin of the Statue were found to consist primarily of the basic copper sulfate known as brochantite or CuSO4·3Cu(OH)2. Another less stable form of basic copper sulfate CuSO4·2Cu(OH)2 known as antlerite was also observed in samples taken from areas that are more exposed to the incoming weather in New York harbor. The presence of antlerite supports the contention that acid deposition is promoting undesirable changes in the phase composition of the patina. Analyses were also performed on patina samples that were taken from pieces of the Statue's copper skin that had been removed in the years 1905 and 1980. X-ray powder diffraction of the corrosion product on the 1905 sample showed that it consisted primarily of the stable brochantite phase, while the 1980 sample displayed both copper chlorides as well as the less stable antlerite. Both samples also contained cuprite (Cu2O) which appears to have formed prior to either of the sulfates.

Crystallographic and X-ray powder diffraction data were derived from a sample of (Na0.5Bi0.5)TiO3 synthesized by standard ceramic techniques. The powder data were indexed on a monoclinic cell having the space group P2 or Pm, which differed from a previously reported rhombohedral cell.

A NIST SRM certified to address the issue of crystallite size measurement through a line profile analysis has been under development for several years. In order to prepare the feedstock for the SRM, nano-crystalline zinc oxide was produced from thermal decomposition of zinc oxalate. The thermal processing parameters were chosen to yield particles in two size ranges, one with a distribution centered at approximately 15 nm and another centered at 60 nm. Certification data were collected on a NIST-built diffractometer equipped with a Johansson incident beam monochromator and scintillation detector. Data were analyzed using whole powder pattern modeling to determine microstructural data. The analysis shows domains to be in the form of discs of a fairly small aspect ratio. While both materials exhibit the effects of stacking faults through broadening of specific hkl reflections, their presence in the 60 nm is more difficult to discern. Images of the crystallites obtained with transmission electron microscopy are consistent with the results from the X-ray diffraction analyses.

The wavelength of the characteristic X-radiation for the lighter elements is not constant but is a function of valence state and to a much lesser extent is a function of co-ordination number.

Commercially available X-ray fluorescence equipment is used in detecting shifts in the characteristic radiation for aluminum, sulfur, chlorine, titanium, vanadium and iron. The greatest shift is found in the case of chlorine where, using the NaCl analyzer, a shift of nearly 0.2° 2 θ is obtained in going from the Cl− in cholorides to the Cl+7 in the perchloratc. The wavelength of the Al+3Kα varies slightly as a function of co-ordination number.

Examples are given for using these phenomena in studying minerals and other compounds. The feasibility of extending the study to both heavier and lighter elements is explored.

Recently, the remains of a giant Cretaceous Sauropod (~150 My old) were discovered in the Morrison Formation west of Albuquerque, New Mexico. This dinosaur, tentatively named Seismosaurus, was found in an exceptional state of preservation. Although it has been known since the 180Q's that fossilized bone is often composed of the mineral apatite, very few studies have been conducted to characterize farther the fossilized material. In an effort to gain insight into the state of preservation and Hie processes occurring in the bone since deposition, apatite in bone from Seismosaurus was compared with that from a contemporary elk from the Jemez Mountains, New Mexico, and with well-crystallized mineral apatite using X-ray powder diffraction and profile analysis techniques. Crystallite size/strain analyses were conducted using the Scherrer equation, the Warren-Averbaca and single-line methods, and the Rietveld method using the program GSAS. Heating the contemporary elk bone produced a decrease in the full-width-at-half-maximum (FWHM) of the reflections in the diffraction pattern. This decrease in FWHM is due to a decrease in microstrain along with a minor increase in crystallite size. Results from crystallite size/strain analysis show that both Seismosaurus and contemporary elk bone crystallites are elongate parallel to the c-axis. However, Seismosaurus bone crystallites are larger (-20-65 nm) with less strain than the contemporary elk bone crystallites (-8-20 nm), suggesting that if elk bone is an appropriate analog, then Seismosaurus bone must have undergone recrystallization.

Undoubtedly the most important applications of X-ray fluorescence spectrometry (XRF) have been in the analysis of major elements where the technique provides a unique method of measuring the concentration of all elements having Z > 10 with extremely good precision in a wide range of matrices. However, XRF is in addition a powerful method for trace element analysis. In this discussion, the principles of the method for the trace element analysis of rocks are outlined, its capabilities are summarized, and the advantages and disadvantages of the technique are pointed out.

High-temperature X-ray diffraction with concurrent gas chromatography (GC) was used to study cobalt disulfide cathode pellets disassembled from thermal batteries. When CoS2 cathode materials were analyzed in an air environment, oxidation of the K(Br, Cl) salt phase in the cathode led to the formation of K2SO4 that subsequently reacted with the pyrite-type CoS2 phase leading to cathode decomposition between ~260 and 450 °C. Independent thermal analysis experiments, i.e. simultaneous thermogravimetric analysis/differential scanning calorimetry/mass spectrometry (MS), augmented the diffraction results and support the overall picture of CoS2 decomposition. Both gas analysis measurements (i.e. GC and MS) from the independent experiments confirmed the formation of SO2 off-gas species during breakdown of the CoS2. In contrast, characterization of the same cathode material under inert conditions showed the presence of CoS2 throughout the entire temperature range of analysis.

Hanawaltite, ideally Hg1+6Hg2+O3Cl2, is orthorhombic, Pbma (57), with unit-cell parameters refined from powder data: a=11.790(3), b=13.881(4), c=6.450(2) Å, V=1055.7(6) Å3, a:b:c =0.8494:1:0.4647, Z=4. The strongest six lines of the X-ray powder-diffraction pattern [d in Å (I)(hkl)] are: 5.25 (80)(111), 3.164 (60)(231), 3.053 (100)(041), 2.954 (70)(141), 2.681 (50)(401), and 2.411 (50)(232,341). The mineral is an extremely rare constituent in a small prospect pit near the long-abandoned Clear Creek mercury mine, New Idria district, San Benito County, California. It was found on a single-fracture surface where it is intimately associated with calomel, native mercury, cinnabar, montroydite, and quartz. Individual crystals are subhedral to anhedral, platy to somewhat bladed, and average about 50 μm in longest dimension. The largest known crystal is approximately 0.3×0.3 mm in size and is striated parallel [001]. Hanawaltite is opaque to translucent (on very thin edges), black to very dark brown–black in color, with a black to dark red–brown streak. Other physical properties include: metallic luster; cleavage {001} good; uneven fracture; brittle; nonfluorescent; H<5; calculated density (for the empirical formula) 9.51 g/cm3.

In polished section, hanawaltite is moderately to strongly bireflectant and is pleochroic white (RI) to blue–white (R2). In reflected plane-polarized light, it is white with orange–red internal reflections in very thin grains and at grain margins. The anisotropy is strong with bright metallic blue rotation tints. Measured reflectance values, in air and in oil, are tabulated. Electron-microprobe analysis yielded Hg2O 82.46, HgO 14.27, Cl 3.33, H2O [0.34], sum [100.40], less O=Cl 0.75, total [99.65] wt. %, corresponding to Hg1+6.00Hg2+1.00 [Cl1.43(OH)0.57]Σ2.00O3.00, based on O+Cl=5. After the crystal structure was determined, the original microprobe value for Hg2O, 96.2, was partitioned in a ratio of 6Hg2O:HgO and (OH) was calculated, such that Cl+(OH)=2. The hanawaltite structure consists of undulatory [Hg–Hg]2+ ribbons which roughly parallel (100). The diatomic [Hg–Hg]2+ groups have anion tails which, in turn, serve as cross linkages between dimer ribbons through [Hg2+O2Cl2] planar rhombs. The structure is compared to that of other mercury oxychlorides and each is found to have its own unique structural features. This structural diversity is attributed to the inherent ability of mercury to adopt either metallic or ionic types of bonds. The mineral name honors the late Dr. J. D. (Don) Hanawalt (1903–1987), who was a pioneer in the field of X-ray powder diffraction.

The X-ray fluorescence holography (XFH) method has drawn the attention of many researchers as a novel experimental technique for imaging a three-dimensional local atomic structure around a certain element in a single crystal. Synchrotron radiation (SR) has been mainly used for the measurements because of extremely weak signals that are about 0.3% of isotropic fluorescent radiation. The measurements limited to the use of a SR source clearly hinder from increasing the number of the users. Thus, we developed a laboratory XFH equipment with a conventional X-ray source by using a singly bent graphite monochromator with a large curvature and X-ray detector for a high counting rate. With this equipment, we have successfully demonstrated that high-quality hologram data of a gold single crystal almost equivalent to those with a SR source are obtained. Four different holograms are recorded in the normal and inverse XFH modes. An atomic image reconstructed from these holograms patterns shows a distinct atomic image of Au

X-ray powder diffraction technique and the Rietveld refinement method have been used successfully for the qualitative and quantitative analyses of Pingguo bauxite from Guangxi, China. Qualitative phase analysis shows that the Pingguo bauxite contains diaspore (AlOOH), hematite (Fe2O3), goethite (FeOOH), anatase (TiO2), and kaolinite (Al2(Si2O5)(OH)4). Quantitative Rietveld refinement shows that the weight concentrations of diaspore, goethite, hematite, anatase, and kaolinite for the Pingguo bauxite are 71.9(4)%, 7.0(8)%, 11.3(7)%, 6.5(6)%, and 3.3(9)%, respectively.

Y6Cr4+xAl43−x (x = 2.57); space group P63/mcm, a = 10.8601(1) Å, c = 17.6783(3) Å, V= 1805.7(1) Å3, Z=2; isostructural to Yb6Cr4+xAl43−x, (x=1.76) with two aluminium sites partially occupied by chromium (44% and 27% Cr). YCr4−xAl8+x (x=1.22); space group I4/mmm, a = 9.0299(2) Å, c = 5.1208(2) Å, V=417.55(3) Å3, Z=2, disordered variant of CeMn4Al8 with one chromium site (8f) partially occupied by aluminium (33% Al); X-ray powder diffraction data were collected on a well-crystallized multiphase sample containing 43 wt.% of Y6Cr4+xAl43−x, 27 wt.% of Y2Cr8−xAl16+x, 16 wt.% of Al, 13 wt.% of YAl3, and traces of Y2O3. Structure refinement converged at Rwp = 2.0% and RB = 3.5, 3.6% resp. for a total of 78 parameters and 1190 reflections.

The room temperature X-ray powder diffraction pattern of Fe2GeSe4, a II2 □ IV VI4 semiconducting compound, has been recorded and evaluated. This material was found to be orthorhombic, a=13.069(1), b=7.559(1), c=6.2037(6) Å, V=612.83(9) Å3, Z=4, Dx=5.42 gcm−3. The structure refinement carried out using the Rietveld method indicated that this material crystallizes in space group Pnma (No. 62) with an olivine type of structure. The refinement of 33 parameters led to RWP=15.3%, RP=10.2% for 5251 step intensities and RB=9.44% and RF=9.36% for 913 reflections.

Polycrystalline Mn1.1Fe0.9P0.76Ge0.24 was prepared by mechanical alloying and spark plasma sintering. Neutron diffraction was used to determine the structure of the title compound, and its nuclear and magnetic structures were refined using the Rietveld method. It is found that temperature and magnetic field can induce phase transition between the paramagnetic and the ferromagnetic phases in the material, and the paramagnetic and ferromagnetic phases have very distinct crystal structures and different Ge contents.

Phase diagrams and X-ray powder diffraction patterns provide critical information for thermoelectric (TE) research. We have conducted a survey of phase diagrams and powder diffraction patterns of TE systems in the ASM (American Society for Metals) Metal/Alloy database and ICDD (International Centre for Diffraction Data) PDF (Powder Diffraction File), respectively, for their availability and crystal systems. In this report, we focus on TE materials that have the half-Heusler XYZ structure, and related compounds, based on a set of materials selection rules. We found that among 306 potential XYZ compounds that we have surveyed, 234 have powder diffraction patterns in the PDF, but only 28 have phase diagram information, and 67 do not have any crystallographic information. Among the 234 phases with powder patterns, 84 were reported to have cubic F43m half-Heusler type structure, and the remainder have hexagonal, orthorhombic or other structure types. Some XYZ compounds have both cubic and hexagonal phases. This information will provide the basis for future activities for the improvement of the databases. These activities include filling the missing gaps in both phase equilibria database and the PDF, as well as adding TE and pertinent physical properties to the PDF.

Order-disorder transformations were studied in annealed and high-energy ball-milled near-equiatomic FeCo alloys. X-ray diffraction with Co Kα radiation enables to follow disordering with milling time because of anomalous dispersion.