Analysis by X-ray powder diffraction

Curry, C. J., Rendle, D. F. and Rogers, A. (1982). Pigment analysis in the forensic examination of paints. I. Pigment analysis by x-ray powder diffraction. J. Forensic Set, 22, 173-7. [260t, 26It]... 

Curry, C. J., et al. "Pigment Analysis in the Forensic Examination of Paints I. Pigment Analysis by X-Ray Powder Diffraction." Journal of the Forensic Science Society 22 (1982), 173-177. 

US patent 6,723,728, Polymorphic and other crystalline forms cis-FTC [106], The present invention relates to polymorphic and other crystalline forms of (—)-and ( )-cA-(4-amino-5-fluoro-l-(2-(hydroxymethyl)-l,3-oxathiolan-5-yl)-2(lH)-pyrimidinone, or FTC) [106]. Solid phases of (—)-cz>FTC that were designated as amorphous (—)-FTC, and Forms II and III were found to be distinguishable from Form I by X-ray powder diffraction, thermal analysis properties, and their methods of manufacture. A hydrated crystalline form of ( )-cA-FTC and a dehydrated form of the hydrate, were also disclosed, and can similarly be distinguished from other forms of FTC by X-ray powder diffraction, thermal properties, and their methods of manufacture. These FTC forms can be used in the manufacture of other forms of FTC, or as active ingredients in pharmaceutical compositions. Particularly preferred uses of these forms are in the treatment of HIV or hepatitis B. 

Structural and textural characterisation of pure SBA-15 and hybrid GFP/SBA-15 Pure SBA-15 and GFP/SBA-15 hybrid were characterised by X-ray powder diffraction, HRTEM and volumetric analysis. Calcined SBA-15 (Fig. 1, curve A) show the typical XRD pattern of an ordered hexagonal network of mesopores with (10), (11) and (20) reflections. The presence of well resolved (11) and (20) peaks indicate that the calcined material used for the preparation of the hybrid materials have a long-range order. The hexagonal XRD pattern was still clearly observed in the hybrid material (GFP/SBA-15), as all the three main reflections were found (Fig. 1, curve B), indicating that the sonication and the GFP physical adsorption does not affect the framework integrity of the material. 

Four samples of faujasite were synthesized at Si/Al ratios of 2.61, 2.80, 2.97 and 3.03 using published methods from seeded slurries (8-9) and using proprietary methods. One additional sample of Si/Al ratio 2.58 was purchased from Union Carbide. The samples were characterized by X-ray powder diffraction, by surface area measurements, and by wet chemical analysis. The results of these measurements are contained in Table I. 

The single-crystal to single-crystal nature and the steric course of the photodimerization of thiocoumarin (102) to (+)-a t/-head-to-head dimer (103) in the inclusion complex were investigated by x-ray crystallographic analysis and x-ray powder diffraction spectroscopy [54],... 

An early investigation of the TbNiSb compound showed that it had the MgAgAs-type with a = 0.6327 (Dwight, 1974), from an X-ray powder analysis of an alloy arc melted under argon and annealed at 973 K. Pecharsky et al. (1983a) and Hartjes and Jeitschko (1995) confirmed the crystal structure and obtained the lattice parameters as a = 0.6302 and a = 0.6304, respectively, by X-ray powder diffraction. For experimental details, see ScNiSb and LaNiSb respectively. 

Hillier, S. (2003). Quantitative analysis of clay and other minerals in sandstones by x-ray powder diffraction (XRPD). Int. Assoc. Sedimentol. Spec. Pub. 34, 213-251. 

Abstract. Gas interstitial fullerenes was produced by precipitation of C6o from the solution in 1,2 dichlorobenzene saturated by O2, N2, or Ar. The structure and chemical composition of the fullerenes was characterized by X-ray powder diffraction analysis, FTIR spectroscopy, thermal desorption mass spectrometry, differential scanning calorimetric and chemical analysis. The images of fullerene microcrystals were analyzed by SEM equipped with energy dispersive X-ray spectroscopy (EDS) attachment. Thermal desorption mass spectroscopy and EDS analysis confirmed the presence of Ar, N and O in C60 specimens. From the diffraction data it has been shown that fullerite with face centered cubic lattice was formed as a result of precipitation. The lattice parameter a was found to enhance for precipitated fullerene microcrystals (a = 14.19 -14.25 A) in comparison with that for pure C60 (a = 14.15 A) due to the occupation of octahedral interstices by nitrogen, oxygen or argon molecules. The phase transition temperature and enthalpy of transition for the precipitated fullerene microcrystals decreased in comparison with pure Cgo- Low temperature wet procedure described in the paper opens a new possibility to incorporate chemically active molecules like oxygen to the fullerene microcrystals. 

The samples used were a standard Na-A zeolite and five nitrogeneous types of zeolite A, or N-A.(18) The N-A zeolites are siliceous analogues of zeolite A, synthesized with tetramethyl-ammonium cation. The Si Al ratio varied from 0.94 (NaA) to 3.54 for the most siliceous N-A sample.t The ratios were determined by wet chemical analysis, and the structure type and absence of impurity phases were confirmed by X-ray powder diffraction techniques. Adsorption measurements (oxygen, -183°C) showed a zeolite A content of greater than 90%. 

All of the treated zeolite solids, both "filtrate" samples and "slurry" samples, were further analyzed by X-ray powder diffraction. The chemical compositions were determined by standard wet chemical analysis, and the filtrates were analyzed for Si02 and AI2O3 following titration. The results show that crystallinity was fully maintained in the solids and that the chemical reactions described in this work are confirmed by the analytical data and mass balances. 

The next stage of characterization focuses upon the different phases present within the catalyst particle and their nature. Bulk, component structural information is determined principally by x-ray powder diffraction (XRD). In FCC catalysts, for example, XRD is used to determine the unit cell size of the zeolite component within the catalyst particle. The zeolite unit cell size is a function of the number of aluminum atoms in the framework and has been related to the coke selectivity and octane performance of the catalyst in commercial operations. Scanning electron microscopy (SEM) can provide information about the distribution of crystalline and chemical phases greater than lOOnm within the catalyst particle. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) can be used to obtain information on crystal transformations, decomposition, or chemical reactions within the particles. Cotterman, et al describe how the generation of this information can be used to understand an FCC catalyst system. 

Shankland, K., David, W. I. E. and Sivia, D. S. (1997). Routine ab initio structure determination of chlorothiazole by X-ray powder diffraction using optimized data collection and analysis strategies. J. Mater. Chem., 1, 569-72. [111]... 

Protactinium metal reacts with hydrogen to form the black hydride, PaHj, which is isostructural with other actinide trihydrides it has only been prepared in submilligram amounts and identified by X-ray powder diffraction analysis (125). 

Preparation and Characterization of Lanthanide and Actinide Solids. Standard crystalline lanthanide and actinide phosphates were prepared by literature procedures (16-18) and characterized by X-ray powder diffraction, FTIR spectroscopy, and thermogravimetric analysis (TGA). Europium was used as an analogue of the trivalent actinides. Metal-phytate solids were generated by mixing Eu(III), U(VI), or Th(IV) nitrate solutions with 0.1 M phytic acid at pH 5 and metal.phytate ratios of 1 1 2 1, and 4 1. The metal phytates precipitated immediately. The resulting slurries were stirred at 85 °C for 30 days and sampled periodically for analysis of the solids by TGA, X-ray powder diffraction, and FTIR. The rate of phosphate release to the solution was monitored colorimetrically. 

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