An orthorhombic fully ordered structural model is proposed for vaterite [space group Ama2, a=8.4721(5) Å, b=7.1575(7) Å, c=4.1265(4) Å, Z=4, and V=250.23(4) Å3]. It is based on a microtwinning hypothesis, with three domains rotated by 120° along the orthorhombic a axis, regenerating a pseudohexagonal habit. The solution came from direct space ab initio calculations applied to the powder diffraction data. However, five weak superstructure reflections seen in single-crystal and powder diffraction experiments, leading to a six times larger unit cell, are still unexplained.

Two applications of parametric Rietveld refinement employing a newly developed robust computer program are presented. The first application focuses on the parametric kinetic analysis of the reactions involving phase transitions of various polymorphic forms of copper phthalocyanine pigments. The second application concerns the parameterization of crystallite size with respect to experimental temperature. XRPD data for nanocrystalline titanium dioxide measured in dependence on temperature are used in this case study. Both the applications were realized with the help of the developed program in combination with the launch mode of topas® software.

An in situ time-resolved XRD system for hydrothermal reaction has been developed in order to investigate the phase evolution during autoclave process in autoclaved aerated concrete (AAC) formation. The system includes a novel autoclave cell for transmission XRD with thin beryllium windows, a two-dimensional photon-counting pixel array detector, and uses high energy X-rays from a synchrotron radiation source. The temperature and pressure inside the cell are extremely stable during hydrothermal reaction over the course of several hours. The system was utilized for the formation reaction of AAC. Phase evolution was clearly observed, including several intermediate phases, and detailed information on the structural changes during the hydrothermal reaction were obtained.

The crystal structures of four samples of anhydrite, CaSO4, were obtained by Rietveld refinements using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data and space group Amma. As an example, for one sample of anhydrite from Hants County, Nova Scotia, the unit-cell parameters are a = 7.00032(2), b = 6.99234(1), c = 6.24097(1) Å, and V = 305.487(1) Å3 with a > b. The eight-coordinated Ca atom has an average <Ca-O> distance of 2.4667(4) Å. The tetrahedral SO4 group has two independent S-O distances of 1.484(1) to O1 and 1.478(1) Å to O2 and an average <S-O> distance of 1.4810(5) Å. The three independent O-S-O angles [108.99(8) × 1, 110.38(3) × 4, 106.34(9)° × 1; average <O-S-O> [6] = 109.47(2)°] and S-O distances indicate that the geometry of the SO4 group is quite distorted in anhydrite. The four anhydrite samples have structural trends where the a, b, and c unit-cell parameters increase linearly with increasing unit-cell volume, V, and their average <Ca-O> and <S-O> distances are nearly constant. The grand mean <Ca-O> = 2.4660(2) Å, and grand mean <S-O> = 1.4848(3) Å, the latter is longer than 1.480(1) Å in celestite, SrSO4, as expected.

Polycrystalline AgIn3Te5 synthesized by melt-quench technique has been analyzed using proton induced X-ray emission (PIXE), X-ray diffraction (XRD), and selected area electron diffraction. PIXE analysis yielded the content of Ag, In, and Te, respectively, to be 9.76%, 31.18%, and 59.05% by weight. Structure refinement was carried out considering those space groups from I- and P-type tetragonal systems which possess 4 symmetry and preserve the anion sublattice arrangement of the chalcopyrite structure (space group: I42d) as well. The results showed that AgIn3Te5 synthesized by melt-quench method crystallizes with P-type tetragonal structure (space group: P42c; unit-cell parameters a = 6.2443(8) and c = 12.5058(4) Å), the presence of which was corroborated by selected area electron diffraction studies.

Crystal structure of Ca1-x/2AlSi(N3-xOx):Eu2+ (x ∼ 0.11) has been characterized using an X-ray powder diffractometer and a transmission electron microscope equipped with an energy dispersive X-ray analyzer (EDX) and an electron energy loss spectrometer (EELS). The title compound is orthorhombic with space group Cmc21, Z = 4, unit-cell dimensions a = 0.979780(7) nm, b = 0.565197(4) nm, c = 0.506356(3) nm, and V = 0.280404(3) nm3. The atom ratio Al:Si was determined to be 1:1 by EDX, and the presence of O atoms in the crystal structure was confirmed by EELS. The x-value and the atomic coordinates of the final structural model were determined by the Rietveld method. The maximum-entropy methods-based pattern fitting (MPF) method was used to confirm the validity of the structural model, in which conventional structure bias caused by assuming intensity partitioning was minimized. The reliability indices calculated from MPF are Rwp = 9.18%, S = 1.17, Rp = 6.77%, RB = 1.91%, and RF = 0.86%. Atomic arrangements of the final structural model are in an excellent agreement with the three dimensional electron-density distributions determined by MPF.

We reported the surface morphology and electrical property of super-thin Pt films, ∼2 nm thick, deposited on 6H-SiC (0001) substrates and subsequently annealed from 400 to 1000 °C. The surfaces of the films were found to have a feature of islands growth, and the sizes of the islands increased with increasing annealing temperature. Free carbon, produced by selective reactions between Pt and SiC, diffused toward the top surface across the product layers due to low solubility and composition gradient of carbon throughout the reaction zone. A dramatic change of electrical conductivity of the films was observed. A mechanism analysis reveals that the origin came from the contribution of aggregation of islands on the surface and formation of Pt silicides and a thin layer of crystalline graphite.

The RuSb2Te compound has been synthesized and structurally characterized from powder X-ray diffraction data. RuSb2Te has the skutterudite structure, Im3 symmetry, unit-cell parameter a = 9.2665(1) Å, V = 795.70(1) Å3, Z = 8, and Dc = 7.88 g/cm3. The Sb and Te atoms randomly occupy the crystallographic 24g position; no indications of ordering of Te and Sb atoms have been detected.

The microstructural evolution of Fe–Mn–C austenitic steels, which exhibit outstanding high-ductile deformation in their plastic regions, was characterized by line-profile and texture analyses. The convolutional multiple whole profile fitting procedure was used for a line-profile analysis of 2θ−θ diffraction data to evaluate variations of crystallite size, dislocation density, and dislocation arrangement. A substantial refinement of the crystallite size proceeded at an early deformation stage. In addition, the dislocation density increased with an increase in the tensile strain. Texture evolution was characterized by the analysis of orientation distribution functions. Three texture components grew with an increase in the tensile strain. According to the pole figure describing the full width at half maximum (FWHM) distribution of the 220 reflection, the nontextured grains had more microstructural defects than the textured grains. To evaluate the microstructural defects in detail, the 220 reflection observed at each texture orientation was analyzed by the single-line-profile method. The crystallite size and dislocation density were almost comparable, irrespective of the kind of texture component. The crystallite size of the nontextured grains was also comparable to that of the textured grains, whereas the nontextured grains had a dislocation density several times that of the textured grains.

Two selected members of the homologous series An+2BBn′O3n+3 (A=Sr and Ca; B and B′=Co) have been investigated for their crystal structures because of their potential applications as thermoelectric materials. A combined Rietveld refinement and spin-polarized magnetic geometry optimization technique was employed for the structural studies. Both the n=3 member, (Sr0.8Ca0.2)5Co4O12, and the n=4 member, Sr6Co5O15, have distorted hexagonal perovskite-related structures that possess one-dimensional cobalt oxide chains separated by alkaline-earth cations. The linear chains consist of one unit of CoO6 trigonal prism alternating with n units of CoO6 octahedra. Crystal structures and reference powder X-ray diffraction patterns of (Sr0.8Ca0.2)5Co4O11 [P3c1, a=9.4196(2) Å, c=19.9857(6) Å, V=825.83 Å3, and Dx=5.358 g/cm3] and Sr6Co5O15 [R32, a=9.497 64(12) Å, c=12.3956(2) Å, V=968.34 Å3, and Dx=5.455 g/cm3] are reported.

CaMnO3 is a parent compound for various manganite systems exhibiting useful physical properties. Therefore, its structural and elastic properties are of general interest. In this paper, P–V equation of state of stoichiometric CaMnO3 is determined using energy dispersive X-ray diffraction. The measurements were carried out at a synchrotron beamline F2.1 (Hasylab, DESY) with samples compressed in a cubic-anvil diffraction press, MAX80, for pressures ranging up to 4.84 GPa. The experimental bulk modulus of CaMnO3, derived from the variation in the unit-cell volume with pressure by fitting the Birch–Murnaghan equation of state, is 154.4(3.3) GPa. The results are discussed on the basis of experimental and theoretical data for CaMnO3 and related compounds.

Hydrothermal formation reaction of tobermorite in the autoclaved aerated concrete (AAC) process has been investigated by in situ X-ray diffraction. High-energy X-rays from a synchrotron radiation source in combination with a newly developed autoclave cell and a photon-counting pixel array detector were used. XRD measurements were conducted in a temperature range 100–190°C throughout 12 h of reaction time with a time interval of 4.25 min under a saturated steam pressure. To clarify the tobermorite formation mechanism in the AAC process, the effect of Al addition on the tobermorite formation reaction was studied. As intermediate phases, non-crystalline calcium silicate hydrate (C-S-H), hydroxylellestadite (HE), and katoite (KA) were clearly observed. Consequently, it was confirmed that there were two reaction pathways via C-S-H and KA in the tobermorite formation reaction of Al containing system. In addition, detailed information on the structural changes during the hydrothermal reaction was obtained.

A suitable external standard method which was first described by O’Connor and Raven (1988) (“Application of the Rietveld refinement procedure in assaying powdered mixtures,” Powder Diffr. 3, 2–6) was used to determine the quantitative phase composition of a commonly used Ordinary Portland Cement (OPC). The method was also applied in order to determine amorphous contents in OPC. Also investigated were the impact of atomic displacement parameters and the microstrain on the calculated amorphous content. The investigations yielded evidence that said parameters do indeed exert an influence on the calculated amorphous content. On the basis of the data produced we can conclude that the method used is entirely to be recommended for the examination of OPC. No significant amorphous content could be proven in the OPC used.

X-ray powder diffraction data, unit-cell parameters and space group for a new chiral Kemp’s acid diamide, C18H28N2O3, are reported [a = 12.456(2) Å, b = 12.471(2) Å, c = 12.088(2) Å, β = 99.003(2)°, unit-cell volume V = 1854,48 Å3, Z = 4, space group P21]. All measured lines were indexed and are consistent with the P21 space group. No detectable impurity was observed.

The structure of [Al2(pydc)2(μ2-OH)2(H2O)2]n(pydc = 2,5-pyridinedicarboxylate) was successfully determined from powder X-ray diffraction data. The compound crystallizes in the triclinic system (space group P -1) with a = 6.7813(1) Å, b = 7.4944(1) Å, c = 8.5013(1) Å, α = 95.256(1)°, β = 102.478(1)°, γ = 108.979(1)°. The structure consists of aluminum ions coordinating N and O in distorted octahedra, sharing an edge through two hydroxide ions. These dinuclear complexes are connected by pydc ions, which at one end coordinate by nitrogen and oxygen and only by oxygen at the other end. The pydc orientation is reversed in the neighboring pydc, forming double stranded chains interconnected by the aluminum dinuclear complexes in a ladder-like arrangement along [001].

The compound NH4Fe[Fe(CN)6]·xH2O—a commercially available “Prussian blue” pigment—crystallizes in the Fm3m space group, a=10.232(1) Å, based on X-ray powder diffraction (XRPD) data. XRPD investigations of other commercially available “Prussian blue” pigments and oil paints were undertaken. Results for the pigments showed that the XRPD techniques were able to differentiate several different Prussian blue phases that differed only slightly in chemical compositions. Results for the oil paints allowed for the determination of the major crystalline phases used as fillers. However, on the basis of XRPD investigations of oil paints prepared in our laboratory containing a mixture of true Prussian blue Fe4[Fe(CN)6]3·14H2O and BaSO4 (a common filler), the pigment was detectable only in concentrations higher than 2%. This result suggests that XRPD may not be a preferred technique for the identification of Prussian blue in paintings and other works of art because the concentration of this pigment in such materials is commonly less than 2%.

Coatings of plasma sprayed hydroxyapatite (HAp), incubated in simulated body fluid for periods varying from 1 to 56 days, were characterized using conventional laboratory X rays. Quantitative phase analysis, employing TOPAS software, showed an opposite trend in the two main phases of the coating, viz., HAp and tetracalcium phosphate (TTCP). The former increased within the first 7 days of incubation whilst the latter decreased during the same period; both phases stabilized with further incubation. The crystallinity of the coatings exhibited a trend similar to that of HAp i.e., an increase in the early stages of incubation stabilization with further incubation. Results of residual stress determined with Bruker’s D8 Discover and analyzed with LEPTOS software, showed both the normal stress tensor components, σ11 and σ22, to be tensile, relaxing significantly in the early stages of incubation before stabilizing with further incubation.

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.

N-derivatives of 4-chloro-3,5-dimethylphenoxyacetamide—2-(4-chloro-3,5-dimethylphenoxy)-N-(4-fluorophenyl)acetamide, 2-(4-chloro-3,5-dimethylphenoxy)-N-(3-chloro-4-fluorophenyl) acetamide, 2-(4-chloro-3,5-dimethylphenoxy)-N-[4-chloro-3-(trifluoromethyl)phenyl] acetamide, 2-(4-chloro-3,5-dimethylphenoxy)-N-[3-chloro-4-methylphenyl]acetamide, 2-(4-chloro-3,5-dimethylphenoxy)-N-(2,4,6-tribromophenyl) acetamide, 2-(4-chloro-3,5-dimethylphenoxy)-N-pyridin-2-ylacetamide, 1-[(4-chloro-3,5-dimethylphenoxy)acetyl]-4-methylpiperazine, and 1-benzyl-4-[(4-chloro-3,5-dimethylphenoxy)acetyl]piperazine—have been characterized by X-ray powder diffraction. These organic compounds are potential pesticides. Experimental 2θ peak positions, relative peak intensities, values of d and Miller indices, and unit-cell parameters are presented.

CdTe nanorods and various branched nanostructures with different crystal structures were have successfully prepared via the catalyst-assisted vacuum thermal evaporation (CVTE) technique using various experimental parameters. SEM and XRD studies were carried out on the as-prepared CdTe nanostructures. The results show that the morphologies and crystal structures of the products were strongly influenced by the growth conditions and the mole ratios of Bi and CdTe. In the high mole ratio (0.08:1) of Bi and CdTe, CdTe branched nanostructures of CdTe were obtained, while nanorods of CdTe were formed at a lower mole ratio of 0.05:1. The crystal structure of products is either Zinc blende or a two-phase mixture of zinc blende and wurtzite. The content of the wurtzite phase were found to increase with increasing growth temperature. Our results also reveal that high growth temperature tends to form the wurtzite phase, and stacking faults may exist in materials grown in higher temperatures. These nanostructures grow following the vapor–liquid–solid (VLS) mechanism.