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Laboratory X-ray Powder Diffraction Data (laboratory + x-ray_powder_diffraction_data)
Selected AbstractsStructural characterization of anhydrous naloxone- and naltrexone hydrochloride by high resolution laboratory X-ray powder diffraction and thermal analysisJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2007Kunihisa Sugimoto Abstract The crystal structures of the analgesic compounds anhydrous naloxone and naltrexone hydrochloride were determined ab initio from high resolution laboratory X-ray powder diffraction data. Both compounds crystallize in the orthorhombic space group P212121 with lattice parameters of a,=,14.6588(10) Å, b,=,17.4363(9) Å, c,=,7.96200(22) Å, and V,=,2035.06(23) Å3 for naloxone hydrochloride and a,=,15.4560(5) Å, b,=,14.9809(4) Å, c,=,7.84121(18) Å, and V,=,1815.58(11) Å3 for naltrexone hydrochloride. The crystal structure of anhydrous naloxone hydrochloride forms one-dimensional chains through hydrogen bonds. In the crystal structure of anhydrous naltrexone hydrochloride, two-dimensional sheets are formed by hydrogen bonds. The dehydration processes of naloxone hydrochloride dehydrate and naltrexone hydrochloride tetrahydrate was analyzed by DTA, DSC, TG, and MG. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 3316,3323, 2007 [source] Crystal Structure and Thermoelectric Properties of YAl3C3JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2007Koichiro Fukuda The crystal structure of YAl3C3 was refined from laboratory X-ray powder diffraction data (CuK,1) using the Rietveld method. The crystal structure is hexagonal (space group P63mc, Z=2) with lattice dimensions a=0.342157(4) nm, c=1.72820(1) nm, and V=0.175217(3) nm3. The final reliability indices were Rwp=9.94% (Rwp/Re=1.18), Rp=7.36%, RB=1.77%, and RF=1.03%. The compound shows an intergrowth structure with electroconductive [YC2] thin slabs separated by Al4C3 -type [AlC] layers. This material had thermoelectric properties superior to those of the layered carbides Zr2[Al3.56Si0.44]C5, Zr2Al3C4, and Zr3Al3C5 in the temperature range of 500, 1073 K, with a maximal power-factor value of 1.96 × 10,4 W·(m·K2),1 at 1073 K. [source] Structures of six industrial benzimidazolone pigments from laboratory powder diffraction dataACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2009Jacco Van De Streek The crystal structures of six industrially produced benzimidazolone pigments [Pigment Orange 36 (, phase), Pigment Orange 62, Pigment Yellow 151, Pigment Yellow 154 (, phase), Pigment Yellow 181 (, phase) and Pigment Yellow 194] were determined from laboratory X-ray powder diffraction data by means of real-space methods using the programs DASH and MRIA, respectively. Subsequent Rietveld refinements were carried out with TOPAS. The crystal phases correspond to those produced industrially. Additionally, the crystal structures of the non-commercial compound `BIRZIL' (a chloro derivative of Pigment Yellow 194) and of a dimethylsulfoxide solvate of Pigment Yellow 154 were determined by single-crystal structure analyses. All eight crystal structures are different; the six industrial pigments even exhibit five different hydrogen-bond topologies. Apparently, the good application properties of the benzimidazolone pigments are not the result of one specific hydrogen-bonding pattern, but are the result of a combination of efficient molecular packing and strong intermolecular hydrogen bonds. [source] Structure determination of seven phases and solvates of Pigment Yellow 183 and Pigment Yellow 191 from X-ray powder and single-crystal dataACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2009Svetlana N. Ivashevskaya The crystal structures of two industrially produced laked yellow pigments, Pigment Yellow 183 [P.Y. 183, Ca(C16H10Cl2N4O7S2), , phase] and Pigment Yellow 191 [P.Y. 191, Ca(C17H13ClN4O7S2), , and , phases], were determined from laboratory X-ray powder diffraction data. The coordinates of the molecular fragments of the crystal structures were found by means of real-space methods (simulated annealing) with the program DASH. The coordinates of the calcium ions and the water molecules were determined by combining real-space methods (DASH and MRIA) and repeated Rietveld refinements (TOPAS) of the partially finished crystal structures. TOPAS was also used for the final Rietveld refinements. The crystal structure of ,-P.Y. 183 was determined from single-crystal data. The , phases of the two pigments are isostructural, whereas the , phases are not. All four phases exhibit a double-layer structure, built from nonpolar layers containing the C/N backbone and polar layers containing the calcium ions, sulfonate groups and water molecules. Furthermore, the crystal structures of an N,N -dimethylformamide solvate of P.Y. 183, and of P.Y. 191 solvates with N,N -dimethylformamide and N,N -dimethylacetamide were determined by single-crystal X-ray analysis. [source] Synthesis and crystal structure determination of two dispiro compounds from laboratory x-ray powder diffraction dataCRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2008A. M. Moustafa Abstract The crystal structures of the dispiro compounds 1,3,4,8,10,11-Hexaphenyl-13-methyl-1,2,8,9,13-pentaazadispiro[4.1.4.3]tetradeca-2,9-dien-6-one (3a) and 4,11-Bis(4-methoxyphenyl)-13-methyl-1,3,8,10-tetraphenyl-1,2,8,9,13-pentaazadispiro-[4.1.4.3]tetradeca-2,9-dien-6-one (3b) have been determined at room temperature from X-ray powder diffraction data using the method of simulated annealing as implemented in the programs DASH and TOPAS. Subsequent Rietveld refinements using the data collected to 1.5 Å resolution yielded R-Bragg values of 2.2% for (3a) and 3.7% for (3b). It was found, that both compounds crystallize in the monoclinc space group P 21/n with lattice parameters of a = 17.1656(5) Å, b =13.8128(3) Å, c = 16.1016(5) Å, and , = 103.7330(2)° for (3a) and a = 17.2529(8) Å, b = 13.8729(5) Å, c =16.1287(10) Å, and , = 103.6910(3)° for (3b). Both compounds exhibit a distorted hexagonal close type of packing (hcp) of the molecular centers of gravity. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||