Modern powder diffraction employing computer-controlled diffractometers now allows quantitative analytical methods to use the whole diffraction trace rather than only individual peaks. Two such methods are in common use: the Rietveld method, which refines the crystal structures of the component phases as part of the matching calculation, and the pattern-fitting method, which uses reference patterns from a database. Potential accuracies of these methods seems to be around 1% absolute. The most severe limitation on the potential accuracy of these methods is particle statistics, which has been reviewed in considerable detail.

The compound Na2ZnV2O7 with an åkermanite-type structure has been synthesized. It has a tetragonal unit cell, a=8.2711(4), c=5.1132(2) Å, and crystallizes with P-421m symmetry, Z=2. Its crystal structure has been refined from a combination of X-ray and neutron powder diffraction data. The structure contains layers of corner-sharing VO4 and ZnO4 tetrahedra, the former in pairs forming pyrovanadate V2O7 units. The sodium atoms are positioned between the layers, with a distorted antiprismatic coordination of oxygen atoms.

Precise X-ray powder diffraction data are given for two germanides, CoGe and Co5Ge7. The refined unit cell parameters for CoGe are a=11.630(1) Å, b=3.8014(3) Å, c=4.9347(3) Å and β=100.889(8)° (space group C2/m, Pearson symbol mC16) with volume of the unit cell 214.24(2) Å3; the figures of merit are M20=96, F30=77 (0.0085, 46). The refined unit cell parameters for Co5Ge7 are a=7.6262(4) Å and c=5.8017(5) Å (I4mm, tI24) with volume of the unit cell 337.42(3) Å3; the figures of merit are M20=204 and F22=130(0.0068, 25). The dependence on composition of the unit cell parameters of CoGe is discussed in terms of specific defect structures.

A series of iron-doped lead titanate PbTi(1−x)FexO(3−δ) samples in the x = 0–1 composition range was prepared using sol–gel synthesis at a calcination temperature of 700 °C. The room temperature CuKα powder diffraction data collected from x = 0, 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.125, 0.15, 0.175, 0.2, and 0.3 samples were analyzed using the Rietveld method. Magnetoplumbite (PbFe12O19) secondary phase formation was observed at compositions x = 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1. Fe-composition dependent decrease of tetragonal distortion has been observed. According to Vegard's law, the B-site iron solubility limit in the lead titanate host was found to be approximately 10 mol% (x = 0.1). Homogeneous distribution of dopants below the solubility limit was evidenced by the linear behavior of unit-cell parameters. The absence of a cubic phase and the persistence of distorted oxygen octahedra indicated the existence of ferroelectric properties even at the x = 0.3 composition. Beyond x = 0.3, the P4mm tetragonal model was determined to be invalid possibly because of oxygen defect driven structural changes, mainly tilting Fe-polyhedra.

Powder X-ray diffraction data are reported for La1−xSrxCo0.8Fe0.2O3 (x=0.2, 0.4) and La0.8Ba0.2Co0.8Fe0.2O3. The powders were prepared by thermal decomposition of metal-containing complex solutions. All compositions have rhombohedral unit cells. In hexagonal setting, the cell parameters are a=5.4451(2) Å, c=13.2553(2) Å for La0.6Sr0.4Co0.8Fe0.2O3; a=5.4556(3) Å, c=13.1999(2) Å for La0.8Sr0.2Co0.8Fe0.2O3 and a=5.4795(1) Å, c=13.2983(5) Å for La0.8Ba0.2Co0.8Fe0.2O3. The space group is probably R3c (167) for all three compositions.

Crystal and X-ray powder diffraction data are presented for the title compound. The powder pattern was indexed and refined on a monoclinic cell with a=17.356(6) Å, b=3.528(1) Å, c=11.285(1) Å, β=94.23(2) Å. The cell volume and Dm=1.772 g/cm3 give Z=4. The space group could not be determined with certainty. The planes of the urate anions likely are stacked parallel or nearly parallel to (010).

Recent developments in instrumentation mean that chemical analysis of large drill cores taken for geological purposes can be performed rapidly at sub-millimetre scales using core scanners equipped with energy-dispersive X-ray fluorescence spectrometers. The present study describes the development of a calibration for the Itrax Core Scanner (Cox Analytical, Sweden), intended for whole cores of coal-seam sections, without the need for sample preparation. The calibration was developed for key major elements (Al, Si, P, S, K, Ca, Ti, and Fe) based on pressed pellets of reference coals, allowing semi-quantitative and, at times, quantitative analyses. The influence of core curvature and surface roughness compared with an ideal flat-surface was also examined using model samples, and their influence on the apparent sample composition evaluated.

A full-pattern fitting procedure based on the Rietveld method was applied to electron diffraction ring patterns of a two-phase system, exhibiting the co-presence of zinc sulfide (sphalerite) and zinc oxide (Wurtzite). Bright and dark field (DF) images reveal the presence of micrometric aggregates, composed of quasi-spherical nanosized crystallites. These conventional transmission electron microscopy imaging methods provide a general morphological characterization of the specimens although, in the present case, they are not suitable for a detailed characterization of the microstructural features of the analyzed samples. Owing to the overlap and broadening of the diffraction rings of the two phases, DF images cannot provide a satisfactory picture of the individual crystallites of each single phase. To overcome this limit, the mentioned Rietveld approach was applied to model the electron diffraction data. The crystalline domain size and relevant shapes for both phases were successfully evaluated using the proposed methodological approach. The excellent results obtained in the microstructural characterization of the nanostructured multiphase samples demonstrate the capability of this technique, that may represents a fully quantitative method for the routine characterization of crystalline nanomaterials.

Nonmetallic crystals with a variety of structures and chemical compositions have been exposed to fission spectrum neutrons in a core position of the Low Intensity Test Reactor (LITR), Oak Ridge, and examined by X-ray diffraction techniques. Wherever possible, single crystals were employed, and the neutron dosages ranged between 1019 and 1021 neutrons/cm2 at a temperature of approximately 85°C. In no case was a special technique used for examining radioactive materials because the problem of heavy induced radioactivity was greatly reduced by working withcrystals weighing a milligram or less. Both film and counter measurements were employed.

The unit cell dimensions of minerals in the smectite group, regular and random mixed-layer groups, and halloysite shown in the Mineral Powder Diffraction File (1986) have been refined by least-squares analysis in the hexagonal system with a primitive lattice with indices restricted to hk or 00l reflections. Trioctahedral minerals have larger a unit-cell dimensions than dioctahedral minerals.

The structural models of three synthetic Al-substituted goethite specimens have been refined from the neutron data, including crystallographic determinations of the Al levels and H positions. The d-I data were calculated for the final models. A relationship between the c unit cell parameter and Al content has been extended to the entire goethite-diaspore solid-solution system, which makes the regression equation procedure simpler and more accurate. A second prospective H site could not be confirmed because of the quality of existing neutron data. However, it is hoped that a further neutron powder diffraction study of a synthetic, fully deuterated goethite material may allow the existence of the site to be demonstrated.

The ε-phase is hexagonal, space group P63/mmc. For the composition Pb7Bi3 the following data were determined, a = 3.5058(1) Å c = 5.7959(5) Å, Vol. = 61.687 Å3(5), Dc = 11.17 Mg m−3. Filings from single crystal material were used to obtain powder data by the Guinier method and the X-ray results were in accordance with single crystal neutron diffraction data. Transition to the superconducting state took place in the interval 8.3 K–8.55 K.

Two compounds with compositions around n=14 and n∼5.4 (n=Bi/Mo molar ratio) have been prepared by solid-state reaction with five heating/grinding cycles at 800 °C. The lattice constants of both compounds can be related to the fluorite-type structure of δ-Bi2O3. Bi14MoO24 has been indexed as an orthorhombic pseudotetragonal (√2×√2×1) superstructure: a=7.812 (±0.005) Å, b=7.762 (±0.005) Å, c=5.7716 (±0.0007) Å (but a+b=15.5750±0.0020). For orthorhombic (3×5×3) Bi38Mo7O78: a=16.8236 (±0.0027) Å, b=28.6182 (±0.0045) Å, c=16.9082 (±0.0027) Å.

Most electrolytic zinc plants have to deal with dissolved magnesium in their process liquors, as zinc sulphide concentrates contain small amounts of magnesium. Applied magnesium bleed methods are generally expensive and environmentally unfriendly. Recently, a new approach was suggested and discussed, which involves selective magnesium fluoride precipitation from purified zinc sulphate solutions. X-ray fluorescence measurements of these precipitates indicated that the ratio Mg:F is not 1:2 as would be expected if the precipitate was MgF2, which should be formed on a theoretical basis. It was inferred that fluoride was partly substituted by hydroxyl groups. Analytical techniques such as infrared absorption spectrometry, X-ray diffraction, and thermogravimetry were combined in order to verify this hypothesis. The precipitate indeed appeared to be a magnesium fluoro- hydroxide compound containing physically bound water. The results contribute to the understanding of the required operating conditions of the proposed process.

A model for the crystalline structure of Ba2YCu0.25W0.75O6 solid solution is given. The model proposed a perovskite ordered structure, with a cubic unit cell made from eight perovskite-like units and having a symmetry described by the space group Fm3m. The crystalline structure was refined by the Rietveld technique, giving RF=0.048 for 82 reflections. The solid solution was characterized by the following parameters: Z=4, Mr=613.2, a=8.43630(8) Å, V=600.42(1) Å3, Dx=6.78 g cm−3, μ=209.04 mm−1, and F(000)=1047. The model assumed that copper and tungsten atoms, which were ordered with Y atoms, had the same local environment. Therefore, it was only a first approximation to the crystalline structure.

In this study, we report the characterization of a 304L stainless steel cylindrical projectile produced by additive manufacturing. The projectile was compressively deformed using a Taylor Anvil Gas Gun, leading to a huge strain gradient along the axis of the deformed cylinder. Spatially resolved neutron diffraction measurements on the HIgh Pressure Preferred Orientation time-of-flight diffractometer (HIPPO) and Spectrometer for Materials Research at Temperature and Stress diffractometer (SMARTS) beamlines at the Los Alamos Neutron Science CEnter (LANSCE) with Rietveld and single-peak analysis were used to quantitatively evaluate the volume fractions of the α, γ, and ε phases as well as residual strain and texture. The texture of the γ phase is consistent with uniaxial compression, while the α texture can be explained by the Kurdjumov–Sachs relationship from the γ texture after deformation. This indicates that the material first deformed in the γ phase and subsequently transformed at larger strains. The ε phase was only found in volumes close to the undeformed material with a texture connected to the γ texture by the Shoji–Nishiyama orientation relationship. This allows us to conclude that the ε phase occurs as an intermediate phase at lower strain, and is superseded by the α phase when strain increases further. We found a proportionality between the root-mean-squared microstrain of the γ phase, dominated by the dislocation density, with the α volume fraction, consistent with strain-induced martensite α formation. Knowledge of the sample volume with the ε phase from the neutron diffraction analysis allowed us to identify the ε phase by electron back scatter diffraction analysis, complementing the neutron diffraction analysis with characterization on the grain level.

Subsolidus phase equilibrium of Na2O–Sm2O3–B2O3 system has been investigated mainly by solid-state reaction and powder X-ray diffraction method. There are nine definite three-phase regions and three ternary compounds determined under present experimental conditions. A novel compound Na3SmB2O6 was found and confirmed in this system, along with its two homogeneous compounds Na3REB2O6 (RE = Pr, Eu) synthesized for the first time. The indexing results showed that all three compounds crystallize in the monoclinic space group P21/c (No.14) with the same structure type as both Na3NdB2O6 and Na3GdB2O6. The lattice parameters (a, b, and c) of new borates Na3REB2O6 (RE = Pr, Sm, Eu) decrease linearly with a decreasing radius of RE ion, which obeys the Lanthanide-contraction rule. The existence of a trigonal BO3 group in the Na3REB2O6 (RE = Pr, Sm) compounds was confirmed by analysis of their infrared absorption spectra. Thermal stabilities of the three new borates have been investigated.

A general least-squares technique for X-ray diffraction line broadening analysis has been developed. The technique can be used to determine single, double, and triple line broadening effects caused by small particle sizes, microstrain, stacking faults, or all three presented in a closed-packed hexagonal nanomaterial. The technique was applied to characterize the microstructure of β-Ni(OH)2, a negative electrode material in nickel-metal hydride (NiMH) batteries. Double line broadening effects caused by both small crystallite sizes and stacking faults in β-Ni(OH)2 were detected and analyzed. Triple line broadening effects caused simultaneously by small crystallite sizes, microstrain, and stacking faults were detected in β-Ni(OH)2 after activation and charge-discharge cycle tests. The triple line broadening effects were found to be selective and most pronounced for diffraction lines with h−k=3n±1. The broadening effects were larger when l=even, but smaller when l=odd. The shape and the average size of the crystallites, microstrain, and stacking fault probability in β-Ni(OH)2 changed dramatically after activation and charge-discharge cycles. The method was also applied to characterize and investigate the microstructure of nano ZnO materials. Results indicate that no selective broadening appears in the XRD patterns of the nano ZnO materials. The average crystallite sizes were different slightly, and the stacking fault probabilities differed significantly with different dopants.

The crystal structure of a new compound Li2Mg2(WO4)3 has been determined by means of X-ray powder diffraction. Li2Mg2(WO4)3 belongs to the orthorhombic system, with space group Pnma and the lattice parameters are: a = 5.1129 Å, b = 10.462 A, and c = 17.612 Å at room.temperature. Its measured density is Dm = 5.48 g/cm3, and each unit cell contains four formula weights.

The thermal behavior and decomposition reaction of Prussian blue (PB) (Fe43+[Fe2+(CN)6]3·xH2O) was studied under inert atmosphere of argon by simultaneous thermogravimetry and differential scanning calorimetry, from room temperature up to 900 °C, with a heating rate of 5 K min−1. Parallel to the thermogravimetric measurements, the thermal process was monitored by in situ X-ray powder diffraction (XRD) technique under nitrogen atmosphere. The thermogravimetric data show six steps, corresponding to different stages of the decomposition reaction; comparable results are also obtained by in situ XRD. In addition, a set of PB samples heated up to selected temperatures (190, 300, 370, 540, 680, and 790 °C) were ex situ analyzed by powder XRD and Mössbauer spectroscopy. It is found that PB exhibits a negative thermal expansion prior to the water release from its crystalline lattice. Above 300 °C, the decomposition is based on the release of cyanogen gas from the PB structure. At 370 °C, a cubic iron cyanide compound is formed, while at higher temperatures several iron carbides were found. The subsequent thermal treatment of these carbides leads to the formation of metallic iron and graphite.