X-ray powder diffraction data, unit-cell parameters and space group for peiminine, C27H43NO3, are reported (a = 30.2026 Å, b = 5.8468 Å, c = 14.4344 Å, β = 96.9456°, unit-cell volume V = 2530.23 Å3, Z = 2 and space group P21). All measured lines were indexed and are consistent with the P21 space group. No detectable impurity was observed.

A new Ca1/3Sb1/6Bi1/2PO4 “CaSb0.50Bi1.50(PO4)3” phosphate has been synthesized by conventional solid-state reaction techniques at 900 °C in air atmosphere. Their crystallographic structures were determined at room temperature from X-ray powder diffraction (XRPD) data using the Rietveld analysis. CaII 1/3SbV 1/6BiIII 1/2PO4 material possesses the high-temperature BiPO4 monoclinic structure variety. It crystallizes in monoclinic system with P21/m space group and the cell parameters are: a = 4.9358(1) Å, b = 6.9953(2), c = 4.7075(1) Å, and β = 96.2(1)°. Their structure can be described as composed of alternating edge-sharing AO8 (A = Ca, Sb, Bi) bisdisphenoids and PO4 tetrahedra forming chains parallel to the b axis. Every AO8 polyhedron is surrounded by six PO4 and every PO4 tetrahedron is surrounded by six AO8 polyhedra. Infrared spectroscopic study was used to obtain further structural information.

Exact and approximate mathematical models for the effects of sample transparency on the powder diffraction intensity data are examined. Application of the formula based on the first-order approximation about the deviation angle is justified for realistic measurement and computing systems. The effects of sample transparency are expressed by double convolution formulas applying two different scale transforms, including three parameters, goniometer radius R, penetration depth μ−1, and thickness of the sample t. The deconvolutional treatment automatically recovers the lost intensity and corrects the peak shift and asymmetric deformation of peak profile caused by the sample transparency.

X-ray diffraction, selected area electron diffraction, and high-resolution transmission electron microscope techniques were used to investigate the crystalline structures of one-dimensional tungsten oxide nanowires prepared by the hydrothermal method. The as-synthesized products were found to exhibit increasing crystallinity with increasing reaction time, and tungsten oxide nanowires have crystalline defects, including stacking faults, dislocations, and vacancies. The results on the crystal defects help us to obtain a better understanding of the temperature-dependent morphological evolution of the ultrathin nanowires synthesized under different thermal processes.

The giant gypsum crystals of Naica cave have fascinated scientists since their discovery in 2000. Human activity has changed the microclimate inside the cave, making scientists wonder about the potential environmental impact on the crystals. Over the last 9 years, we have studied approximately 70 samples. This paper reports on the detailed chemical–structural characterization of the impurities present at the surface of these crystals and the experimental simulations of their potential deterioration patterns. Selected samples were studied by petrography, optical and electronic microscopy, and laboratory X-ray diffraction. 2D grazing incidence X-ray diffraction, X-ray μ-fluorescence, and X-ray μ-absorption near-edge structure were used to identify the impurities and their associated phases. These impurities were deposited during the latest stage of the gypsum crystal formation and have afterward evolved with the natural high humidity. The simulations of the behavior of the crystals in microclimatic chambers produced crystal dissolution by 1–4% weight fraction under high CO2 concentration and permanent fog, and gypsum phase dehydration under air and CO2 gaseous environment. Our work suggests that most surface impurities are of natural origin; the most significant anthropogenic damage on the crystals is the extraction of water from the caves.

The crystal structure of lacosamide form I has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques (density functional theory). Lacosamide form I crystallizes in space group P21 (#4) with a = 10.677 73(5), b = 4.799 68(2), c = 13.639 16(9) Å, β = 91.6331(10)̊, V = 698.719(6) Å3, and Z = 2. Van der Waals interactions are important in the crystal structure. Two N–H···O hydrogen bonds form C1,1(4) chains along the b-axis. Several weaker C–H···O hydrogen bonds to the ketone oxygens also contribute to the packing energy. These C–H···O extend both along the b-axis and in the ac-plane, and help link the molecules in three dimensions. The powder pattern has been submitted to International Centre for Diffraction Data for inclusion in the Powder Diffraction File™.

The fluorite-related anion-excess β-Pb1−xFexF2+x (0.25 ≤ x ≤ 0.27) orthorhombic crystal structure is approached from powder diffraction data. A 1 × 1 × 2 fluorite supercell is found to describe the main aspects of the structure, which would have ideally the Pb3FeF9 formula (x = 0.25) (space group Cmmm, a = 5.9926(1), b = 5.5781(1), c = 11.5208(3) Å), and would include a complete [FeF4]∝−1 perovskite plane, orthogonal to the c axis. However, there is large Pb substitution (44%) on the perovskite Fe site as well as Fe substitution (∼25%) on one of the two main Pb sites. A strong relationship with the fully ordered crystal structure of Pb8MnFe2F24, which can be expressed as Pb1−xMxF2+2/3x (x = 0.273), is discussed, suggesting that both phases may have infinite [M3F14]∝ ribbons in common.

The crystal structure of levocetirizine dihydrochloride Form I has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Levocetirizine dihydrochloride Form I apparently crystallizes in space group P21/n (#14) with a = 24.1318(21), b = 7.07606(9), c = 13.5205(7) Å, β = 97.9803(4)°, V = 2286.38(12) Å3, and Z = 4. The crystal structure consists of interleaved double columns of cations and anions along the short b-axis. The hydrogen bonds link the cations and anions along this axis. Each protonated nitrogen atom forms a strong N–H⋯Cl hydrogen bond to one of the chloride anions. The carboxylic acid group also forms an H-bond to Cl56, resulting in a ring with a graph set R1,2(10). The centrosymmetric P21/n model for the crystal structure of levocetirizine dihydrochloride is better than the non-centrosymmetric P21 model, even though levocetirizine is a chiral molecule; the sample exhibits weak second-harmonic generation, and three weak peaks which violate the glide plane are observed. The centrosymmetric model is better by statistical, graphical, and energetic measures, as well as by chemical reasonableness. To accommodate the chiral molecule in a centrosymmetric space group, the chiral central carbon atom was disordered over two half-occupied positions, so that each cation site could be occupied by a cation of the correct chirality. A powder pattern from a Le Bail extraction of this synchrotron data set is included in the Powder Diffraction File™ as entry 00-066-1627.

Four manganese carbonyl complexes: CpMn(CO)3 (1) and its phenylvinylidene derivatives Cp(CO)2Mn=C=CHPh (2), [Cp(CO)2Mn]2(μ-C=CHPh) (3), and Cp(CO)2Mn=C=C(Ph)–C(Ph)=C=Mn(CO)2Cp (4) have been studied by X-ray powder diffraction and their unit cell parameters are reported. The monoclinic cell parameters found for complex (1) are a=12.0479(7) Å, b=7.0614(5) Å, c=10.9172(6) Å, β=117.626(2)°, Z=4, space group P2(1)/a (No. 14). The orthorhombic cells parameters for complex (2) are a=10.5240(12) Å, b=33.1105(48) Å, c=7.5007(9) Å, Z=8, space group PCCN (No. 56); for complex (3) are a=15.3545(17) Å, b=15.3966(18) Å, c=8.0033(7) Å, Z=4, space group P21212121 (No. 19). The parameters found for complexes (1–3) are in good agreement with those obtained from single crystal X-ray diffractometry. The single crystal structure of complex (4) has not been studied. The orthorhombic cell parameters for complex (4) found by X-ray powder diffraction method are a=10.0986(9) Å, b=33.2937(27) Å, c=7.4139(5) Å, Z=4, space group P21 (No. 4).

The compound Er2BaF8 is prepared by heating appropriate amounts of BaF2 and ErF3 at 900 °C for 18 h in a dry argon filled quartz ampoule. The polycrystalline sample obtained was characterized by a Rietveld refinement of the observed powder diffraction data. This compound crystallizes in a monoclinic lattice with unit cell parameters: a=6.9620(2), b=10.4960(3), c=4.2541(1) Å and β=99.685(1)°, V=306.14(1) Å3, Z=2, (space group C 2/m, No. 12). The structure analysis reveals the presence of one kind of Ba and Er atoms in the unit cell. There are three different kinds of fluorine atoms, namely F1, F2, and F3 in the ratio of 8:4:4. The Er atoms form a square-antiprism polyhedron with eight fluorine atoms, which share three of its edges to form a ring of six ErF8 polyhedra. The rings of ErF8 polyhedra are connected via two opposite corners along the c-axis of the unit cell. The voids formed within the rings are occupied by Ba atoms, which maintain a twelve-coordination polyhedron with the fluorine atoms. As per the Rietveld analysis, the F3 site may exist as a disordered state by shifting the fluorine atom from the two-fold axes. © 2004 International Centre for Diffraction Data.

Powder diffraction data for 2-aminophenalenone at 295 K (P21/n, Z=4) are given, strong lines: 7.54/X, 7.26/9, 3.34/3. The cell parameters found are a=3.7213(3), b=16.550(2), c=15.095(2) Å, β=92.61(2)°. The crystal structure was determined using powder data and refined giving Rb=0.089. Disordered molecules form stacks along [100] with interplanar spacing of 3.48 Å.

Preparing dry specimens from liquid samples for XRF analysis avoids introducing caustic or hazardous liquids into the instrument. Several modifications were made to a dried residue specimen preparation method for quantifying gallium in plutonium metal in order to improve the method accuracy and precision. Ion exchange chromatography was utilized to remove the plutonium prior to casting the dried residue specimens. This, coupled with several other changes, improved the method relative error from ∼5% to less than 1%. These results are sufficient for routine sample analysis and are almost comparable to results from the established process using liquid specimens. However, the analysis of radioactive liquid specimens is unnecessary for quantifying the plutonium gallium content using this dried residue approach

Cement references were reviewed and whole pattern methods were developed for the quantitative phase analysis (QPA) of Type I Portland Cements. A set of control references were established for phase identification and quantitative analysis using laboratory diffractometers. Both RIR and Rietveld whole pattern fitting methods were used in the analyses. A block refined, parameter restricted, Rietveld method produced the best QPA results by comparison with known mixtures. Similar to prior literature findings, care has to be taken because of the severe peak overlap of the major calcium silicate and calcium aluminate phases in Portland cement and the complexity of the chemistry and structures involved. Two of the four major phases identified are doped supercells and the major C3S phase is also disordered.

The trihydrated potassium trioxalato-chromate(III), K3(Cr(C2O4)3).3H2O, crystallizes in the monoclinic system with:

the space group is P21/c.

Powder diffraction patterns have been calculated for nine isostructural rhombohedral M2(SO4)3 (M = Sc, Ti, V, Cr, Fe, Ga, Y, Rh, In) phases, and for four isostructural monoclinic M2(SO4)3 (M = V, Fe, In, Tl) phases. The pattern for monoclinic Fe2(SO4)3 is the first reported for this phase. Because structure data are available only for the two Fe2(SO4)3 polymorphs, the powder patterns of the other trivalent metal sulfates were approximated using the structure data of the isostructural Fe phases with the scattering factors and previously determined cell parameters of the various metal sulfates. These calculated patterns are termed an approximation by isostruduralism.

The calculated patterns were used to evaluate reference powder data for these phases in the Powder Diffraction File (PDF). All but two of the PDF patterns were found to differ substantially from the calculated patterns in the stronger peaks used for identification, and to be missing weak peaks that may be confused for impurities during phase identification.

X-ray powder diffraction data are reported for the trihydrated (A3N), the dihydrated (A2N), and the anhydrous ammonium trioxalatoaluminate (III) (AN). A3N is triclinic with space group . A2N and AN are monoclinic with space groups P21/c and P21/n respectively. The stability domains are A3N: –7.8 to 86 °C; A2N: 86 to 102 °C; AN: 102 to 180 °C.

Materials in a high radioactive environment undergo structural changes. X-ray diffraction (XRD) is commonly used to study the micro-structural changes of such materials. Therefore, a safe procedure is required for the preparation of specimens. In this paper, a simple methodology for the preparation of radioactive powder specimens to be analyzed in a non-nuclearized laboratory diffractometer is presented. The process is carried out inside a shielded glove box, where the milling of the radioactive sample and specimen preparation occurs. Minimum amount of sample is required (<20 mg), which is drop-casted on a polyether ether ketone (PEEK) foil and glue-sealed inside a disposable plastic holder for a safe handling of the specimen. One example using neutron-irradiated granite is shown, where unit-cell parameters and crystal density of the main phases were calculated. The developed methodology represents an easy and affordable way to study neutron irradiated materials with low activity at laboratory scale.

X-ray powder diffraction and optical data are presented for a vanadium-rich dravite from Silver Knob, Mariposa County, California, U.S.A. The limited compositional variability observed for vanadium-rich dravite is due to the presence of a Tschermaks substitution whereby the substitution of Al for Si in the tetrahedral ring is charge balanced by trivalent for divalent cation substitution in the octahedral sites in the structure. Vanadium-rich dravite is uniaxial negative with ε = 1.646(2) and ω = 1.676(2). Refined unit cell dimensions are a = 15.9599(10) and c = 7.1889(2); F30 = 111(0.009; 30); M20 = 80; and Dx = 3.07. An indexed X-ray powder diffraction pattern is also presented.

X-ray powder diffraction data for two ionic salts containing imidazole (Him) complexes of the magnesium(II) ion, [Mg(Him)4(H2O)2]Cl2 and [Mg(Him)6](NO3)2, are reported. Their crystal and molecular structures were determined by simulated annealing and full-profile Rietveld refinement methods. [Mg(Him)4(H2O)2]Cl2 was found to crystallize in the monoclinic system with space group C2/c, a=12.3980(3) Å, b=11.0234(2) Å, c=14.4691(3) Å, and β=107.024(1)°. [Mg(Him)6](NO3)2 crystallizes in the trigonal R-3 space group with a=b=12.4631(4) Å and c=14.9449(6)Å. Both species contain centrosymmetric complexes, and Mg is octahedrally coordinated by six imidazoles, as in [Mg(Him)6](NO3)2, or by four imidazoles and two water molecules, as in [Mg(Him)4(H2O)2]Cl2. Additional analytic, thermogravimetric, calorimetric, and spectroscopic characterizations were also performed.