X-ray powder diffraction studies

X-ray powder diffraction studies are perfonned both with films and with counter diffractometers. The powder photograph was developed by P Debye and P Scherrer and, independently, by A W Hull. The Debye-Scherrer camera has a cylindrical specimen surrounded by a cylindrical film. In another commonly used powder... 

Mohammad Jafar Soltanian Fard-Jahromi and Ali Morsali (2010) Sonochemical synthesis of nanoscale mixed-ligands lead(II) coordination polymers as precursors for preparation of Pb2(S04)0 and PbO nanoparticles thermal, structural and X-ray powder diffraction studies. Ultrason Sonochem 17(2) 435-440... 

A room temperature powder X-ray diffraction pattern for Na8[GaSi04]6(C104)2 Sodalite with Si as an internal standard for phase identification in the reaction products has been studied. X-ray powder diffraction study confirms the cubic structure of Na8[GaSi04]6(C104)2 sodalite synthesized... 

Cheetham, N. W.H. and Tao, L. (1998). Variation in crystalline type with amylose content in maize starch granules X-ray powder diffraction study. Carbohydrate Polymers. 36, 277-284. 

Earlier X-ray powder diffraction studies by de Haan and Visser provided similar results. These authors investigated the impact of the selenium content on the structure type of the crystals and deduced the existence of eight-memteed ring molecules but were unable to decide whether the crystals consisted of binary compounds of sulfur and selenium or simply of Seg and Sg. 

While the stoichiometric salt formations with HX are clear-cut if the acid cannot be removed simply by evacuation, there may be questions of salt formation versus complexation in solid-solid reactions between acids and bases. This point has been suitably addressed with IR spectroscopy and X-ray powder diffraction studies of solid carboxylic acids and amine bases of varying strengths that were ground or milled together [34]. Yields are not given, but it may be assumed that quantitative reactions occurred in all stoichiometric mixtures. 

At the same time the structures in the solid state of Mc2Mg and Et2Mg were determined by X-ray powder diffraction studies . Both compounds form polymeric chains as the result of the bridging of two methyl groups between two magnesium atoms, rendering the magnesium atoms almost perfectly tetrahedrally coordinated. 

An x-ray powder diffraction study performed on the sodium salts of ( )-and (+)-etodolac showed these salts to be mixtures of amorphous and crystalline materials [12]. Scanning electron microscope studies showed that the amorphous form of ( )-etodolac sodium salt transformed into various crystal forms when exposed to 75% relative humidity conditions for 7 days. The crystalline form of (+)-etodolac sodium salt transformed into swollen rod-like crystals under the same exposure conditions. 

A synchrotron X-ray powder diffraction study of (Sc2C2) Cs4 showed that the lozenge-shaped SC2C2 unit is encapsulated by the T>2d-Cs4 fullerene, as shown in Fig. 14.2.11(d). The Sc-Sc, Sc-C and C-C distances in the SC2C2 unit are 429, 226 and 142 pm, respectively. 

Ruthenium(III) fluoride can be prepared by the reduction of ruthenium(V) fluoride with either iodine or sulfur at elevated temperatures2312 or in an impure form by reduction of [RuF5]4 with ruthenium metal.2313 It is a dark brown powder shown by X-ray powder diffraction studies to consist of RuF6 corner shared octahedra, (with Ru—Ru separations of 3.37 A).2314 Neutron diffraction studies reveal no evidence of magnetic ordering even at 4.2 K.2315... 

Vitale G., Bull L. M., Morris FL E. and Cheetham A. K., Combined neutron and X-ray powder diffraction study of zeolite CaLSX and a H NMR study of its complex with benzene. J. PAys. Chem. 99 (1995) pp. 16087-16092... 

X-ray powder diffraction photographs. The quartz capillaries used for X-ray powder diffraction studies were dried under vacuum (10 Torr) at 1070 K for 24 h before being transferred to the dry Ar atmosphere of a Vacuum Atmospheres Corporation DRILAB. X-ray powder samples were prepared as previously described (17). Photographs were taken using a 45-cm-circumference G.E. camera with Straumanis loading, the radiation being CuKa with a nickel filter. 

Moreover, polymers 6 and 8 were pyrolyzed in bulk. These pyrolysis experiments were performed in a slow stream of nitrogen and the samples were heated to 1000°C at a rate of 10°C min", remaining at this temperature for 30 minutes Both of the ceramic products were black powders and in X-ray powder diffraction studies they showed only broad peaks of low intensity, indicating the presence of mainly amorphous material To obtain crystalline materials, the ceramic products were heated slowly to 1400°C where they were held for 5 hours. The X-ray powder diffraction showed exclusively sharp peaks, characteristic of P-SiC, respectively. The increased ceramic yield obtained by pyrolysis of the metal modified carbosilane 8, as compared with the polycarbosilane 6, can be explained by an increased concentration of carbon as impurity, which was additionally evidenced by elemental analysis. 

Maxwell JC (1864) On the calculation of the eqnilibrium and stiffness of frames. Phil Mag 27 294-299 McGreevy RL, Pusztai L (1988) Reverse Monte Carlo simulation A new technique for the determination of disordered structures. Molec Simulations 1 359-367 McGreevy RL (1995) RMC - Progress, problems and prospects. Nuclear Instmments Methods A 354 1-16 Palmer DC, Finger LW (1994) Pressnre-induced phase transition in ciistobalite an x-ray powder diffraction study to 4.4 GPa. Am Mineral 79 1-8... 

Orear J (1982) Least squares when both variables have nncertainties. Am J Phys 50 912-916 Palmer DC, Finger LW (1994) Pressure-indnced phase transition in cristobalite An X-ray powder diffraction study to 4.4 GPa. Am Mineral 79 1-8... 

Parise JB, Chen J (1997) Studies of ciystalhne solids at high pressure and temperature using the DIA multianvil apparatus. Eur J Solid State Inorg Chem 34 809-821 Parise JB, Coibin DR, Abrams L (1995) Stractural changes upon sorption and desorption of Xe from Cd-exchanged zeolite rho A real-time synchrotron X-ray powder diffraction study. Microporous Mater 4 99-110... 

A number of diethyl ether-dihalogenoalane adducts have been prepared and characterized by X-ray powder diffraction studies. The standard enthalpy of formation of HAlCl2,OEt2 was calculated to be — 774.29 kJ... 

O Brien, S. et al.. Time-resolved in situ x-ray powder diffraction study of the formation of mesoporous silicates, Chem. Mater., 11, 1822, 1999. 

X-ray powder diffraction studies. There is a possibility that 84 and 85 still keep a small amount of ether guest moleclules in their inclusion cavities and that these inclusion complex lattices play a role as the seed crystals during complexation in the solid state. This hypothesis was proven to be correct by the following experiments. When a mixture of powdered 84 and a seed crystal of 83 (2 wt.%) was exposed to ethyl ether vapor for 3 h, 84 was converted to 83 in quantitative yield. By similar contact of a powdered mixture of 85 and a seed crystal of 82 (2 wt. %) for 12 h, 85 was converted to 82. Furthermore, contact of a powdered mixture of 12 (98 mg, 0.34 mmol) and 83 (2 mg, 2.1 pmol 2 wt.%, 1.35 mol%) with ethyl ether vapor for 3 h gave 83 in quantitative yield. However, contact of powdered 12 with ethyl ether vapor in the absence of a seed crystal for 72 h did not lead to the formation of any inclusion complexes [47]. 

Redhammer GJ, Dachs E, Amthauer G (1995) Mossbauer spectroscopic and X-ray powder diffraction studies of synthetic micas on the join annite KFe3AlSi30io(OH)2-phlogopite KMg3AlSi30io(OH)2. Phys Chem Minerals 22 282-294... 

Sr2+ ion exchange for Na+ in zeolite X is an example of the occurrence of a phase reaction as a result of the limited solubility of the end members of an ion exchange series. Olson and Sherry (45) have reported an x-ray powder diffraction study that shows that as Sr2+ ions are exchanged into NaX, the cubic unit cell contracts. At 71% Sr loading, the unit cell suddenly expands and a new phase forms that is richer in Sr2+ and has a much more expanded unit cell. Evidence for the presence of 2 solid phases is the double x-ray diffraction pattern that they observed. The new phase has the faujasite structure, an Sr exchange level of 87%, and is in equilibrium with the old phase. As the miscibility gap of 71 to 87% is traversed, the Sr-poorer phase disappears and the amount of the Sr-richer phase increases until at 87% Sr loading, only the expanded phase exists. The lattice parameter data are shown in Figure 8. 

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