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X-ray Diffraction Analysis Shows (x-ray + diffraction_analysis_shows)
Selected AbstractsMolecular Iodine Stabilization in an Extended N···I,I···N AssemblyEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 24 2009Francesco Isaia Abstract The adduct [bis(quinoxaline)-2,2,,3,3,-disulfide·I2], (Q2S2·I2), (1) can be easily synthesised from the reaction of Q2S2 and I2 in CH2Cl2 or, in the absence of any solvent, through diffusion of I2 vapours at 60 °C. X-ray diffraction analysis shows the presence of an extended N···I,I···N assembly in which each I2 molecule links a Q2S2 molecule at both ends through a nitrogen atom to form a polymeric species; the d(I,I) and d(N,I) bond lengths confirm a very weak nitrogen,iodine interaction at the base of the N···I,I···N assembly. DFT calculations provide optimised distances for the N···I and I,I bonds and explanation for the zigzag chain formation: the mPW1PW functional and the B3LYP hybrid functional with a variety of basis sets for the I atomic species [CRENBL, LANL2DZ, LANL2DZ(d,p), LANL08(d), SBKJC, SBKJC polarised-LFK and Stuttgart RLC] have been tested. Compound 1 proved stable up to nearly 100 °C, and the stability is to be mainly attributed to the lattice energy of its polymeric structure then to donor,acceptor stabilisation. The facile insertion of molecular iodine into the Q2S2 network makes this compound an interesting iodine sponge, suitable for I2 storage; moreover, Q2S2 can easily collect and release I2(g) by a temperature-controlled process (60 and 97 °C, respectively). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Dense Alumina,Zirconia Coatings Using the Solution Precursor Plasma Spray ProcessJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2008Dianying Chen For the first time, dense coatings have been made by the solution precursor plasma spray (SPPS) process. The conditions are described for the deposition of dense Al2O3,40 wt% 7YSZ (yttria-stabilized zirconia) coatings; the coatings are characterized and their thermal stability is evaluated. X-ray diffraction analysis shows that the as-sprayed coating is composed of ,-Al2O3 and tetragonal ZrO2 phases with grain sizes of 72 and 56 nm, respectively. The as-sprayed coating has a 95.6% density and consists of ultrafine splats (1,5 ,m) and unmelted spherical particles (<0.5 ,m). The lamellar structure, typical of conventional plasma-sprayed coatings, is absent at the same scale in the SPPS coating. The formation of a dense Al2O3,40 wt% 7YSZ coating is favored by the lower melting point of the eutectic composition, and resultant superheating of the molten particles. Phase and microstructural thermal stabilities were investigated by heat treatment of the as-sprayed coating at temperatures of 1000°,1500°C. No phase transformation occurs, and the grain size is still in the nanometer range after the 1500°C exposure for 2 h. The coating hardness increases from 11.8 GPa in the as-coated condition to 15.8 GPa following 1500°C exposure due to a decrease in coating porosity. [source] Luminescent Property of a Supramolecular Silver(I)-Thiolate Complex Based on Secondary Ag-S Interactions and Hydrogen BondsCHINESE JOURNAL OF CHEMISTRY, Issue 9 2001Wei-Ping Su Abstract The supramolecular silver(I)-thiolate complex [Ag(,2 -SC4N2H4)2(SCN)]n has been prepared from the reaction of AgSCN and pyrimidine-2-thiol in DMF. X-ray diffraction analysis shows that the supramolecular structure exhibits one-dimensional chain through the secondary Ag-S interactions and the chains are further linked by strong hydrogen bonds to form a three dimensional network. The luminescence effect from the silver-centered state of S,Ag LMCT in solid state is different from that in solution due to the secondary Ag-S interactions. [source] Preparation and properties of dynamically cured PP/MAH- g -EVA/epoxy blendsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2009Xueliang Jiang Abstract A method concerning with the simultaneous reinforcing and toughening of polypropylene (PP) was reported. Dynamical cure of the epoxy resin with 2-ethylene-4-methane-imidazole (EMI-2,4) was successfully applied in the PP/maleic anhydride-grafted ethylene-vinyl acetate copolymer (MAH- g -EVA), and the obtained blends named as dynamically cured PP/MAH- g -EVA/epoxy blends. The stiffness and toughness of the blends are in a good balance, and the smaller size of epoxy particle in the PP/MAH- g -EVA/epoxy blends shows that MAH- g -EVA was also used as a compatibilizer. The structure of the dynamically cured PP/MAH- g -EVA/epoxy blends is the embedding of the epoxy particles by the MAH- g -EVA. The cured epoxy particles as organic filler increases the stiffness of the PP/MAH- g -EVA blends, and the improvement in the toughness is attributed to the embedded structure. The tensile strength and flexural modulus of the blends increase with increasing the epoxy resin content, and the impact strength reaches a maximum of 258 J/m at the epoxy resin content of 10 wt %. DSC analysis shows that the epoxy particles in the dynamically cured PP/MAH- g -EVA/epoxy blends could have contained embedded MAH- g -EVA, decreasing the nucleating effect of the epoxy resin. Thermogravimetric results show the addition of epoxy resin could improve the thermal stability of PP, the dynamically cured PP/MAH- g -EVA/epoxy stability compared with the pure PP. Wide-angle x-ray diffraction analysis shows that the dynamical cure and compatibilization do not disturb the crystalline structure of PP in the blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] | |||||||||||||