bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative determination of chrysotile asbestos in bulk materials by combined Rietveld and RIR methods
Authors: Gualtieri A. , Artioli G.
Published: January 2013

Because of their potential to induce a number of pathological diseases and their widespread industrial usage in the past, the fibrous minerals forming asbestos have been the subject of a number of studies in the past. Although quantification of asbestos minerals by optical and electron microscopy (SEM, TEM) is a routine technique in the case of dispersed airborn fibers, the detection and the quantification of small amount of fibrous minerals like chrysotile in bulk materials such as building materials is exceedingly difficult. A method for the detection and evaluation of asbestos minerals in massive samples is described, based on a combination of Rietveld and RIR (Reference Intensity Ratio) methods. Lower detection limits are about 0.5-1.0 wt % for chrysotile, depending on powder pattern, counting statistics, and matrix absorption. The chrysotile wt % determined on powder diffraction profiles collected on a conventional instrument is precise to about 1.0 wt % absolute (relative error in the range 0-10%). The technique is of straightforward application. If compared with the commonly used microscopic or spectroscopic techniques, it is of much advantage from the point of view of time, and the results are more accurate and statistically significant of the bulk material. A model for the cylindrically disordered structure of fibrous chrysotile is especially developed for the simulation of the X-ray powder patterns, and it is proposed here.
Powder diffraction data and Rietveid refinement of the compound Ba2Cl2Cu3O4
Authors: Pitschke W. , Krabbes G. , Mattern N.
Published: January 2013

Indexed X-ray powder diffraction data are reported for the semiconducting compound Ba2Cl2Cu3O4. The structure was refined by the Rietveid technique on the basis of the space group I4/mmm. Refined unit cell dimensions area= 5.5156(1) Å,c= 13.8221(3) Å,V= 420.49 Å3Dx= 4.74 g/cm3,F30= 129(0.0075,30),M20= 121,Rp= 6.58,Rwp= 8.66, andRB= 4.49.
The Reference Intensity Ratio: Its Measurement and Significance
Authors: Davis Briant L. , Kath Randy , Spilde Michael
Published: January 2013

Two methods may be used to measure the reference intensity ratio: (1) by measuring intensities from samples prepared by mixing the analyte and standard together in a known weight ratio and (2) measuring separately the intensities for the analyte peak and reference standard peak from pure phase preparations and by correcting the intensities with mass absorption coefficients. Both methods give identical results that are independent of the difference in mass absorption between analyte and standard. These reference intensity ratios may be universally applied to both matrix flushing and adiabatic procedures in multicomponent analysis providing that preferred orientation, microabsorption, and extinction can be eliminated or greatly minimized in the samples under analysis.
Use of X-Ray Powder Diffraction Rietveld Pattern-Fitting for Characterising Preferred Orientation in Gibbsites
Authors: Deyu Li , O'Connor Brian H. , Roach Gerald I.D. , Cornell John B.
Published: January 2013

A study has been conducted with gibbsite specimens, on the use of Rietveld X-ray powder diffraction (XRPD) pattern fitting for quantitating preferred orientation in powders. This study has shown that an earlier formula gives results which correlate closely with an empirical measure of morphology proposed recently for gibbsite powders, viz., the ratio of the XRPD intensities for the (002) line and the (110, 200) doublet lines. A method is proposed on the basis of this correlation for the correction for preferred orientation of line intensities in gibbsite powder patterns. The correction method appears to have excellent potential for XRPD quantification of gibbsite levels in mixtures, and could have general application for coping with preferred orientation effects in the quantitation of other phases.
X-Ray and Optical Data for a Rare Earth–Poor Eudialyte from the North–Central Alaska Range
Authors: Johnson Neil E. , Gunter Mickey E. , Solie Diana N. , Knowles Charles R.
Published: January 2013

Powder X-ray and optical data have been recorded for a sample of exceptionally rare earth-poor eudialyte (Na12(Ca, REE)6(Fe2+,Mn,Mg)3Zr3(Zr,Nb)x[Si9O27−y(OH)y]2[Si3O9]2(C1,F)z, with x = 0. 1–0.9, y = 1–3 and z = 0.7–1.4) from a pegmatitic vein associated with the peralkaline Windy Fork granite in the north–central Alaska range. The eudialyte is uniaxial positive with ω= 1.6062(2), ε= 1.6138 (3) and microprobe analyses indicate that the sum of REE + Yis less than 0.1 weight percent. Refined unit cell dimensions are: a = 14.2572(4), c = 30.1338(27), Dx= 2.67, F30= 128 (0.006, 42), M20= 76. An indexed powder diffraction pattern is given.
X-ray Powder Diffraction Data for Di-(1-phenylisopropyl)formamide
Authors: Rendle D.F.
Published: January 2013

X-ray powder diffraction data for the compound Di-(1-phenylisopropyl)formamide, C19H23NO are reported. The crystals are monoclinic and the space group P21/c, with a = 10.764(2), b = 14.893(2), c = 10.862(2) Å, β= 108.49(1)°, Z = 4, Dx= 1.132, Dm= 1.120(2) gm/cm3.
“Brooklyn Poly”: The First Major Teaching Center of X-ray Powder Diffraction
Authors: Rose R.N.
Published: January 2013

That very large famous and infamous borough of New York City, namesake of one of the country's most graceful bridges, Brooklyn, was perhaps the least likely of places for the development of a teaching center of international brilliance – and, at that, in the then little known field of X-ray diffraction. Such was the case, however. Where else, it has been asked, could a visiting lecturer on X-ray technique look out at his audience and, to his dismay, find in the front row, Paul P. Ewald, Herman Mark, Isidor Fankuchen and David Harker – respectively, a founding father of X-ray diffraction, a founding father of polymer chemistry, an entrepreneur par excellence in X-ray crystallography, and a major player in macromolecular (proteins) analysis. Only there at the Brooklyn Polytechnic Institute. It was unique in its time and function as the pre-eminent school of learning for the rapidly evolving practices of polymer science and X-ray diffraction.
Lattice Parameters of Bismuth Molybdates Determined with a New High Temperature Diffractometer
Authors: Boon L. , Baas H. de Jonge , Metselaar R.
Published: January 2013

The temperature dependence of the cell parameters is given for Bi2Mo3O12, Bi2Mo2O9, γ-Bi2MoO6 and γ'-Bi2MoO6, and the volume expansion coefficient is derived. A description is given of a high-temperature diffractometer (HTD) for temperatures up to about 1600°C in controlled atmospheres.
X-Ray Powder Diffraction Analysis of Barium Titanyl Oxalate Tetrahydrate
Authors: Louër D. , Boultif A. , Gotor F.J. , Criado J.M.
Published: January 2013

Barium titanyl oxalate tetrahydrate, Ba(TiO)(C2O4)2.4H2O, has been investigated by means of X-ray powder diffraction. Precise powder diffraction data were obtained by a conventional diffractometer with strictly monochromatic radiation. Unit cell dimensions were determined by an indexing program based on the variation of parameters by successive dichotomies. A monoclinic cell was found, a=14.044(2)Å, b=13.812(2)Å, c=13.382(2)Å, β=91.48(1); V=2594.9Å3, which is characterized by the figures of merit M20=46.5 and F30=107(0.0056, 50). The complete powder pattern was reviewed by means of the program NBS*AIDS83 and the 81 first lines were indexed. Structural imperfections were not detected from the diffraction line widths, which are comparable to the instrumental resolution.
X-Ray Powder Diffraction Data and Unit Cells of Ammonium Paratungstate Tetrahydrate
Authors: van Put John W. , Verkroost Theo W. , Sonneveld Eduard J.
Published: January 2013

X-Ray powder diffraction data and unit cell parameters of industrially produced, as well as bench scale prepared, ammonium paratungstate tetrahydrate are reported and compared with current Powder Data File (PDF) (1989) patterns. A least-squares refinement resulted in two slightly different unit cells. Both cells are monoclinic with S.G. = P21/n(14), Z = 2. The density, 4.639(2)kg/m3, calculated from one of these unit cells corresponds reasonably well with a measured value of 4.61 (2). It has, however, not been possible to determine at present why ammonium paratungstate tetrahydrate has two unit cells. No relation between the crystalline form and the method of preparation nor the exact water content could be established.
X-Ray Powder Diffraction Data of a New Compound As4Mo3015
Authors: Hums Erich , Göbel Herbert E.
Published: January 2013

Arsenic molybdate, As4Mo3015, has been investigated by means of X-ray powder diffraction. The diffraction data were collected with a focussing (Guinier-type) transmission diffractometer equipped with a primary-beam monochromator (Ge 111) for CuKα radiation and a scanning position-sensitive detection system. A monoclinic unit cell was determined using an indexing program.
Analysis of the CuKβX-Ray Diffraction Pattern of YAG (Yttrium Aluminium Garnet) by Numerical and Computerized Graphics Techniques
Authors: Berti G. , Palamidese P.
Published: January 2013

Yttrium aluminium garnet, Y3A15O12– YAG, has a powder diffraction pattern that is easy to analyse in principle, but shows very interesting problems. These problems are revealed using an interactive graphics system, UNIRAS, intregated with some of the usual procedures for crystallographic data processing. For example, indexing with the APPLEMAN procedure is improved when the high-angle peaks are properly identified, and the cell parameters then refine to a high precision. Iterations between refinements and graphical analysis allows the operator to identify even some of the very weak peaks in the pattern. Using the peak positions from the refinement, the experimental data can be analyzed for instrumental aberrations and corrections can be applied to improve the accuracy of the cell parameter.
X-Ray Powder Diffraction Data for (1R,2R) -(−)-norpseudoephedrine hydrochloride, (lS,2R)-(+)-norephedrine hydrochloride, and (±)-norephedrine hydrochloride
Authors: Rendle D.F. , Glazier E.J. , Cain P.M.
Published: January 2013

X-ray powder diffraction data for the three title compounds are reported. The crystals of all three compounds are monoclinic and the space group is P21 (No. 4) in each case. (1R, 2R)-(−)- norpseudoephedrine hydrochloride has a = 5.4422(8) Å, b = 8.071(1) Å, c = 11.839(1) Å and P= 101.803(9)°. For (1S,2R)-(+)-nqrephedrine hydrochloride a = 8.457(1) Å, b = 10.337(2) Å, c = 12.575(3) Å, and β = 107.46(1)° and for(±)-norephedrine hydrochloride a = 7.4406(6) Å, b = 9.4557(6) Å, c = 14.5799(8) Å and β= 103.446(7)°.
X-Ray Powder Diffraction Data of a New Compound Na2Ca4Mg2Si4O15
Authors: Hausner Robert , Suppaner Michael
Published: January 2013

Sodium Calcium Magnesium Silicate, Na2Ca4Mg2Si4O15, has been investigated by means of X-ray powder diffraction. Data were obtained by a conventional diffractometer. Unit cell dimensions were determined by an indexing program. A monoclinic cell was found, a = 17.884(2) Å, b = 5.3573(8) Å, c = 7.1796(8) Å, β = 112.71 (1)°; V=634.56 A3.
Indexed Powder Data for Incommensurate Bi2Sr2Ca2Cu3Oz
Authors: Namgung C. , Lachowski E.E. , Irvine J.T.S. , West A.R.
Published: January 2013

The X-ray powder pattern of the Pb-free 110 K superconductor phase Bi2Sr2Ca2Cu3Oz has many lines which belong to an incommensurate supercell. Using electron diffraction photographs as a guide, an indexing scheme for the powder pattern has been obtained. The unit cell has a geometrically orthorhombic subcell a = 5.411 (2), b = 5.420(2), c = 37.29(2) Å. Supercell reflections have indices that are derived from the subcell k, l indices by addition of ± q, where q = nδb + nεc: n = 1,2 …; ε = 0.211(2); ε = −0.78(1).
Sodium Copper Oxalate Dihydrate: Na2Cu (C2O4)2. 2H2O Synthesis, Characterization, Morphology and Optical Properties
Authors: Polou R. , Triche C. , Barbier B. , Pitet G.
Published: January 2013

Crystals of sodium copper oxalate dihydrate [Na2Cu (C2O4)2.2H2,O] were obtained by the gel method, from solutions of oxalic acid and copper chloride. The crystals form blue needles with idiomorphic faces of brilliant luster, permitting goniometric measurements and the determination of the morphology with the aid of crystallographic parameters. Optically the crystals are biaxial negative, 2V = 38°, with a weak dispersion r<v. The orientation of the indicatrix was determined using a universal stage.

Crystals of sodium copper oxalate dihydrate, Na2Cu (C2O4)2.2H2O, were apparently first obtained in 1929 by Riley. Gleizes et al. (1980) undertook a preliminary crystallographic study of crystals obtained by a different technique from Riley's. In the first case, a solution of 33.5 g/L of sodium oxalate was heated and then poured gradually into a nearly saturated solution of copper sulfate until slight turbidity appeared. The turbidity was eliminated and the solution clarified by the addition of a little more sodium oxalate solution. In this way Riley obtained a dark blue solution which after filtration yielded extremely fine sky-blue needle-like crystals, rarely more than 8mm long. In the method of Gleizes et al. (1980), copper oxalate was dissolved in an aqueous solution of sodium oxalate; those authors observed complete dissolution when the molar ratio of sodium oxalate to copper oxalate was near 2. By evaporating the solution, they obtained long, prismatic crystals whose crystallographic constants they determined.

In order to obtain crystals large enough for further crystallographic study, we set out to produce crystals of sodium copper oxalate by the gel method (Triché, 1984). We found that slow crystallization did encourage the formation of large crystals.
The Use of Fourier Self-Deconvolution to Resolve Overlapping X-Ray Powder Diffraction Peaks
Authors: Armstrong Ernest E. , Cameron David G.
Published: January 2013

Fourier self-deconvolution has been successfully applied as a means of obtaining semi-quantitative information by resolving the overlapping peaks in X-ray powder diffractograms collected from mixtures of kaolinite and ripidolite. A series of diffractograms were collected from known mixtures of the two minerals. The diffractograms were then processed using Fourier self-deconvolution over a selected range between 23 and 27° 2θ (encompassing the overlapping peaks of kaolinite (002) and ripidolite (004) at 24.85 and 25.13° 2θ, respectively). Once deconvoluted, areas under individual peaks of kaolinite and ripidolite were calculated using curve fitting. The calculated percentage of kaolinite in the mixtures was then plotted versus the true weight percent of kaolinite. The same procedure was conducted on the original diffractograms using only curve fitting without first deconvoluting. A comparison of results shows that, provided the number of peaks are known, both methods give nearly equal results. However, Fourier self-deconvolution, by increasing the resolution, greatly improves the ability to detect overlapping peaks.
A Study of the Superconducting La2-xSrxCuO4 System by X-Ray Powder Diffraction
Authors: Huang T.C. , Torrance J.B. , Nazzal A.I. , Tokura Y.
Published: January 2013

Room temperature crystalline structures of La2-xSrxCuO4 samples with uncommonly high hole concentrations (p) up to p=0.4, annealed under 1 and 100 bars of oxygen pressure have been analyzed by X-ray diffraction. Results show that the x=0 sample with p=0.09 and superconducting below 20K is orthorhombic at room temperature. The orthorhombic distortion at 300K decreases with increasing x and becomes tetragonal when x reaches 0.08. This orthorhombic-to-tetragonal phase transformation is consistent with previous work. Samples with x≥0.28 and p≥0.31 remain tetragonal but are nonsuperconducting down to 5K. Lattice dimension anomalies have also been observed and are correlated with the sudden appearance of oxygen vacancies, as seen by the hole concentration measurements. Initially, the value of the lattice dimension a decreases and c increases monotonically with increasing x. A sudden increase in a and decrease in c begins when x reaches 0.28 for samples prepared under 1 bar of oxygen indicating a sudden loss of oxygen from the structure. This sudden reversal in lattice dimensions a and c is not present in samples annealed under 100 bars of oxygen pressure suggesting essentially no oxygen vacancies. The increase in c with x of the La2-xSrxCuO4 samples with no oxygen vacancies can be attributed mainly to the result of substituting smaller La+3 ions by larger Sr+2 ions. A study of the variation of c with the hole concentration reveals that the c lattice dimension drops sharply with no change in the hole concentration when oxygen is continuously removed from the lattice caused by an increase of the Sr content in La2-xSrxCuO4.
X-Ray Powder Data for Mellite
Authors: Blanchard Frank N.
Published: January 2013

New X-ray powder data and a refined cell for mellite are presented and evaluated in comparison with the current PDF 28-2001.
Analysis of X-Ray Powder Diffraction Patterns of Perovskite-Like PrNiO3
Authors: Huang T. C. , Parrish W. , Torrance J. B. , Lacorre P.
Published: January 2013

X-ray powder diffraction patterns of orthorhombic- and rhombohedral-distorted perovskite PrNiO3 obtained at room temperature, 200°, 400°, 500°, and 600°C were analyzed and evaluated. An examination of the diffraction profiles shows essentially no line broadening indicating that the PrNiO3 powders synthesized by solid state reaction are well-crystallized and probably strain-free. The reliability and accuracy of the patterns were evaluated, and the figures-of-merit were in triple digits for the 500° and 600°C patterns of the rhombohedral phase and double digits for the more complex orthorhombic diffraction patterns recorded at room-temperature, 200°, and 400°C. Values of lattice parameters refined from the observed diffraction peak positions agree with those obtained from the Rietveld whole-pattern fitting analysis to within 1–2 × 10−4.
Automation of a Filmscanner for Evaluation of Guinier Films and Applications to Determination of Diffraction Data of Pb2Sr2Ho0.625Ca0.375Cu3O8 and Measurement of Thermal Expansion of GeO2
Authors: Jørgensen Jens-Erik
Published: January 2013

A previously manually operated film comparator used to evaluate Guinier films has been automated as a film scanner of the flat film type. The film movement is controlled by a stepper motor and the intensity of the transmitted light is recorded as a function of position on the film. A personal computer controls the stepper motor and records the measurements of the transmitted light intensity. The data quality is judged from refinements of lattice constants for α-SiO2 and ZrO2. The powder pattern for Pb2Sr2Ho0.625Ca0.375Cu3O8 and a high temperature study of the thermal expansion of GeO2 are presented.
Molecular Alloys in the Series of Para-Disubstituted Benzene Derivatives. Part V. The Para-Dibromobenzene Para-Chloroiodobenzene
Authors: Calvet T. , Alcobé X. , Tauler E. , Cuevas-Diarte M. A. , Estop E. , Mondieig D. , Haget Y.
Published: January 2013

The binary phase diagram of para-dibromobenzene and para-chloroiodobenzene is characterized by a partial miscibility with a peritectic invariant. Unit cell parameters have been determined and their variation analyzed as a function of composition.
Nomenclature, Symbols, Units and Their Usage in Spectrochemical Analysis VIII Nomenclature System for X-Ray Spectroscopy
Authors: Jenkins R. , Manne R. , Robin R. , Sénémaud C.
Published: January 2013

This report is one of a series on the nomenclature for spectrochemical analysis issued by the International Union of Pure and Applied Chemistry. It concerns a new notation for X-ray emission lines and absorption edges, to be called IUPAC NOTATION, which replaces the existing Siegbahn notation. It is based upon the energy level designation and has the advantage of being simple and easy to apply to any kind of transition. Moreover, it is consistent with the notations used in electron spectroscopy.

The document first discusses the terms currently used in X-ray spectroscopy and then describes the principles of the IUPAC notation with reference to the X-ray levels and the X-ray transitions. The correspondence between Siegbahn and IUPAC notations for all X-ray lines is given in a table. Finally, the document gives the units and conversion factors used in the X-ray range.
X-Ray Powder Diffraction Data for Two Antihistamines: Clemizole Hydrochloride and Cyclizine Hydrochloride
Authors: Rendle D.F. , Glazier E.J.
Published: January 2013

X-ray powder diffraction data for clemizole hydrochloride (1-p-chlorob-enzyl-2-pyrrolidin-1′-ylmethyl-benziminazole hydrochloride, C19H20ClN3.HCl) and cyclizine hydrochloride (1-benzhydryl-4-methylpiperazine hydrochloride, C18H22N2.HCl) are reported. Crystals of clemizole hydrochloride are monoclinic, space group P21/n with a = 29.940(5) Å, b = 10.963(2)Å, c = 5.515(2)Å, β = 90.98 (3)°, Z = 4 and Dx = 1.330g cm−3. Crystals of cyclizine hydrochloride are orthorhombic, space group Pna21 (or Pnam), with a = 11.816(1)Å, b = 13.609(2)Å, c = 9.999(1 )Å, Z = 4 and Dx = 1.251g cm−3.
Powder Diffraction Data of Some Acentric Tartrates and Tartrato-Antimonates
Authors: Garsche Markus , Tillmanns Ekkehart , Bauer Thomas , Fischer Reinhard X. , Bohaty Ladislav
Published: January 2013

Six acentric tartrates and tartrato-antimonates have been investigated by means of X-ray powder diffraction. Single crystals were obtained by evaporation from aqueous solutions. The compounds have attracted attention because of their electrostrictive and electro-optical effects. Complete crystal data for the six compounds are reported. X-ray powder diffraction patterns for Rb2C4H4O6and Ca [Sb2{C4H2O6}2]·2H2O are given.
Precise Angular Control of Quartz-Cutting by X-Rays
Authors: Parrish William , Gordon Samuel
Published: January 2013

Methods for precise control of the cutting angles of quartz by x-ray measurements are described. The quartz must first be oriented by some other method (usually optically) before the x-ray method can be applied. The sense of direction of the cut is indicated by an arrow drawn on the outer surface of the test cut at the saw and this direction is preserved in making the x-ray measurement. The x-ray technique is an adaptation of the Bragg ionization chamber method and involves measuring the angle between the surface of the test cut or blank and an atomic reference plane parallel (or nearly parallel) to the surface. All measurements are direct, and require no computation. A Gieger-Muller tube operated in the proportional counter region is employed. Accuracy of the method is approximately ±1.5′, the measurement requires about 10-15 seconds, and is used by unskilled help. The procedures for calibrating the x-ray goniometer and measuring various types of cuts are described in detail. Methods involving precise angular adjustments of sections approximately oriented by other methods and the use of reflection intensity differences of certain planes on either side of the optic axis for detecting usable portion of electrical twins and negative and positive directions from Z are described. The methods are applicable to other fields.
Rietveld Refinement of the Crystal Structure of CuF2
Authors: Burns Peter C. , Hawthorne Frank C.
Published: January 2013

The crystal structure of monoclinic CuF2 has been refined by the Rietveld method from X-ray powder diffraction data. The structure is monoclinic, space group P21/n, a = 3.2973(2), b = 4.5624(3), c = 4.6157(3) Å, β = 83.293(3)°, V = 68.96(2) Å3, with Cu+2 at (0,0,0) and F−1 at (−0.04176(68), 0.29410(35), 0.29410(35)). Final RB = 0.97%, RP = 1.99%, Rwp = 2.32%, RWP(expected) = 1.46%. The structure has a rutile-type arrangement, but with a monoclinic distortion that produces a highly distorted octahedral coordination around the Cu2+ ion with equatorial and apical Cu-F distances of 1.92 and 2.32 Å respectively.
Angular Corrections for the Seemann-Bohlin X-Ray Diffractometer
Authors: Rafaja D. , Valvoda V.
Published: January 2013

A method for the correction of peak position for the Seemann-Bohlin X-ray diffractometer, useful for practical application, is presented. The position of diffraction peaks is largely influenced by both the displacement of specimen from the diffractometer circle and the shift of the X-ray tube focus. The described correction method has been used for investigation of thin layers, especially for the precise determination of both lattice parameter and stresses in thin films. The application of the method is illustrated on samples of TiN and ZrN coatings deposited on steel substrates and additionally covered with a thin film of Si or Ta or TaC powder used as an internal standard.
An X-ray diffraction study of pyrolytic manganese dioxide
Authors: Rogers K. D. , Cossins D.
Published: January 2013

The thermal decomposition of aqueous manganese nitrate has been studied under a range of experimental conditions to scientifically assess the pyrolysis processes employed by the tantalum capacitor industry. The crystalline phase and form of the manganese oxides produced are compared by X-ray diffraction and scanning electron microscopy. Those experimental conditions producing materials with the lowest resistivity are identified. The technological significance of the decomposition process is discussed and initial results from a novel pyrolysis technique are presented.
Powder diffraction data for two mixed nitrates CeMI2(NO3)6(MI=Rb,Cs)
Authors: Guillou N. , Auffrédic J. P. , Louër D.
Published: January 2013

Ceric caesium nitrate CeCs2(NO3)6 and ceric rubidium nitrate CeRb2(NO3)6 have been investigated by means of X-ray powder diffraction. Precise data collected with strictly monochromatic radiation (CuKα1) are reported. Monoclinic unit cell dimensions were found by the indexing program DICVOL91 based on the variation of parameters by successive dichotomy. The final refined parameters are: a = 13.5373(7) Å, b = 7.0787(5) Å, c = 8.1672(5) Å, β = 90.813(5)° for the caesium compound and a = 13.0567(5) Å, b = 6.8684(2) Å, c = 8.1786(3) Å, β = 91.436(4)° for the rubidium compound, and the indexings are characterized by the figure of merit F30 equivalent to 245 (0.0033,37) and 194 (0.0040,39), respectively.
Design and use of a prototype long-wavelength powder diffractometer
Authors: Jenkins Ron , Nicolosi J. A.
Published: January 2013

The analysis of crystalline organic phases by X-ray powder diffraction presents special problems, beyond those typically associated with inorganic materials. The large unit cells often associated with organic compounds, combined with the low symmetry of the structures, give rather complicated diffraction patterns that contain many low angle lines. The Bragg–Brentano geometric arrangement employed in most commercial diffractometers gives maximum (d-spacing error at low diffraction angles. This geometry, in turn, means that not only can the large (d-spacing data be of poor quality, but also that much of the low angle data required for the indexing of the pattern is subject to large errors.
Crystallite-size distributions and diffraction line profiles near the peak maximum
Authors: Allegra Giuseppe , Brückner Sergio
Published: January 2013

The effect of crystallite-size distribution on the shape of X-ray diffraction peaks from powder samples is investigated focusing the attention on the region within the top half of intensity. It is shown that, unlike profile tails, this central region can markedly depart from the Lorentzian shape for crystallite-size distributions that are quite acceptable from the physical point of view. Goal of this paper is to correlate the well-known m parameter in the Pearson VII function or the η weight in the pseudo-Voigt function with a number of different distributions of crystallite dimensions ranging from the δ function of all-equal-sized crystals to a very broad distribution. The suitably normalized curvature at the peak is a possible new parameter; its correlation with m and η is shown. Also, a procedure is suggested to derive the volume-average crystal thickness 〈Tw〉 from the FWHM and the knowledge of either m or η.
Low- and high-temperature structures of neopentylglycol plastic crystal
Authors: Chandra Dhanesh , Day Cynthia S. , Barrett Charles S.
Published: January 2013

Plastic crystals, such as neopentylglycol, 2, 2-dimethyl-1,3-propanediol, that exhibit polymorphic behavior are emerging materials for thermal energy storage. The energy is stored isothermally in the γ phase, FCC, during solid-state phase transformations. This γ phase of NPG has been determined as an orientational disordered phase. The low temperature α phase structure, which is of great significance in the evaluation of lattice expansions and other parameters, was first determined in 1961. However, the reported unit cell dimensions and the intensities of the reflections led to erroneous indexing of the powder patterns in binary systems. The α phase structure is redetermined here as monoclinic, M= 104.15 amu, space group P21/n (an alternate setting of , space group No. 14), a = 5.979(1)Å, b= 10.876(2)Å, c=10.099(2)Å, β=99.78(1)°, V=647.2(2)Å3 at 20°(± 1)C, Dx= 1.069 g cm s−3 for Z=4. In this paper the redetermined structure of the α phase of NPG is presented in projections of the atomic positions, in tables, and in calculated powder pattern and these results are compared with those reported by others. The powder patterns obtained from the Bragg–Brentano diffractometer are compared with our calculated pattern from the single crystal data. The structural parameters of the high temperature phase of NPG as determined by a Guinier diffraction system are also reported.
The applicability of powder X-ray diffraction to the quantification of drug substance polymorphs using a model organic system
Authors: Kidd W. Christopher , Varlashkin Peter , Li Chia-yu
Published: January 2013

With a new emphasis on the control of polymorphism in pharmaceutical production, the need for methods to quantify polymorphic forms has arisen. Techniques using X-ray powder diffraction are increasingly being used to characterize the phases of drug substances that exist in multiple crystal forms. Current methods to identify the polymorphic phases in a drug substance include microscopy, infrared spectroscopy, thermal analysis (DSC/TGA), solid state NMR, and X-ray powder diffraction. Of the aforementioned techniques, X-ray powder diffraction provides the most effective approach to identify and quantify the different crystal phases of a pharmaceutical compound. This work is intended as a guide to the characterization and quantification of an organic crystalline system using X-ray diffraction. The approaches suggested are intended to provide assistance not only from an in-process pharmaceutical manufacturing standpoint, but also for routine quality assurance screening of polymorphic drug substances.
Indexed experimental X-ray powder diffraction patterns of Tl0.5Pb0.5Sr2Ca2Cu3Ox (Tl,Pb-1223) and TlSr2Ca2Cu3Ox (Tl-1223)
Authors: Morgan Peter E. D. , Doi Toshiya J. , Nelson Jeffrey G.
Published: January 2013

Indexed experimental powder diffraction patterns of Tl,Pb-1223 and Tl-1223 are presented with a method of determining good cell parameters for the former awkward case where c/a almost exactly equals 4. For Tl,Pb-1223, a = 3.814±0.001 Å, c = 15.267±0.005 Å, for Tl-1223, a = 3.814±0.001 Å, c = 15.302±0.005 Å, both tetragonal, space group P4/mmm.
The Determination of Low Levels of Quartz in Commercial Kaolins by X-ray Diffraction
Authors: Elton N.J. , Salt P.D. , Adams J.M.
Published: January 2013

Legislation in the United States and Canada requires labelling of products containing ≥ 0.1 wt.% crystalline silica. Kaolin clays are used in a variety of industries and usually contain low levels of total (i.e., respirable plus non-respirable) quartz, even after beneficiation. X-ray diffraction procedures have been developed here which are suitable for the quantification of total quartz in commercial kaolins with accuracy sufficient to satisfy the legislation. Separation and analysis of the respirable fraction is not addressed in this paper; however, the procedures described would be applicable to such samples if sufficient were available. Use of the 50.1° 2θrather than the 26.6° 26 (CuKα) quartz peak avoids most of the potential problems of overlap with reflections from other accessory minerals. It is shown that profile fitting techniques and optimised experimental procedures allow the determination of quartz in bulk samples to ± 0.03 wt.% (95% confidence) at the 0.1 wt.% level, and ± 0.1 wt.% at the 1.0 wt.% level, with tolerable data collection times.
Notes on Slits and Monochromators in Accurate Powder Diffractometry
Authors: Timmers J. , van der Pers N.M. , Sprong G.J.M. , de Keijser Th.H. , Delhez R.
Published: January 2013

Limitations in powder diffractometry imposed by scatter slits and/or a diffracted-beam monochromator, which have been ignored in the past, are discussed and mapped quantitatively. These limitations become manifest especially with ωoffsets, i.e.in stress measurements and with ωoscillation to improve the reproducibility of intensities in the presence of too coarse grains. The limitations can only be established with knowledge of slit sizes and with precise alignment of all slits, their holders and the diffracted-beam monochromator. To that end, concise, accurate procedures for obtaining these measurements in-situare proposed.
Powder X-Ray Diffraction Data for Ca2Bi2O5and C4Bi6O13
Authors: Rawn C.J. , Roth R.S. , McMurdie H.F.
Published: January 2013

Single crystals and powder samples of Ca2Bi5O5and Ca4Bi6O13have been synthesized and studied using single crystal X-ray diffraction as well as X-ray and neutron powder diffraction. Unit cell dimensions were calculated using a least squares analysis that refined to a δ2θof no more than 0.03°. A triclinic cell was found with space group , a = 10.1222(7), b = 10.1466(6), c = 10.4833(7) Å. α= 116.912(5), β= 107.135(6) and γ= 92.939(6)°, Z = 6 for the Ca2Bi2O5compound. An orthorhombic cell was found with space group C2mm, a = 17.3795(5), b = 5.9419(2) and c = 7.2306(2) Å, Z = 2 for the Ca4Bi6O13compound.
Improved X-Ray Powder Diffraction Data for Franckeite
Authors: Mottana Annibale , Fiori Salvatore , Parodi Gian Carlo
Published: January 2013

The X-Ray powder diffraction patterns of three franckeite specimens from Bolivia all lack the 2.91 and 2.82 Å reflections of 100 intensity reported in PDF 15-25. A new indexed pattern is given for the franckeite of the San José mine, Oruro.
Interlaboratory Tests of X-Ray Quantitative Phase Analysis
Authors: Dyakonov J. , Mishchenko K. , Hering A. , Unger G. , Korecký J. , Melka K. , Zoubková J. , Raynov N. , Thekhlanova N. , Rischák G. , Sidorenko G. , Volkov M.
Published: January 2013

The results of an international project involving five countries and seven laboratories performing over 400 analyses for testing the interlaboratory reproducibility and accuracy using quantitative powder diffraction are presented in this report. Four natural and four artificial mineral mixtures were examined. The RIR (reference intensity ratio) values for all mineral components were either measured or calculated. The relative standard deviation of the interlaboratory determinations range from 5 to 20 percent (for low concentrations, the relative standard deviations can attain 60% percent). Due to systematic errors, the relative standard deviations of the interlaboratory determinations generally exceed the standard deviations determined by individual laboratories. The best results were obtained when the RIR values were measured independendy in each laboratory.
About Instrument-, Method- and Matrix-Independence in the Working Equations of the Quantitative X-Ray Analysis
Authors: Zangalis K. P.
Published: January 2013

In most of the practical problems of the quantitative X-ray analysis, obtaining working equations including only intensity ratios without the sample mass-absorption coefficient is impossible, unless an internal standard is added to the sample. It is shown that the internal standard may be unnecessary if some chemical data are added to the XRD information used. Experimental results justify this claim.
Crystal Data for Metal Cimetidine Isotiocionates: M(CM)2(NCS)2 (M = Co(II), Ni(II), Cu(II))
Authors: Amigó J.M. , Ochando L.E. , Reventós M.M. , Martínez M.A. , Soto-Tuero L. , Sancho A.
Published: January 2013

Metal cimetidine isothiocyanates, M(C10H16SN6)2(NCS)2, where M = Co(II), Ni(II) and Cu(II), have been investigated by means of X-ray powder diffraction. Unit cell dimensions were determined from powder diffractometer data. Refined cell parameters (monoclinic with a primitive cell), powder data, calculated densities and Z value are presented.
Sigmund Weissmann Pioneering X-ray Crystallographer: From insights into the “pathology of structure” (lattice defects) and physical metallurgy came one of the first laboratories for Materials Science—and a life-long association with the PDF
Authors: Rose Richard N.
Published: January 2013

Music, medicine, escape: Austria, Italy, America. As a very young man, Sigmund Weissmann, before he was 18, had seen the prosperous stability and direction of his youth disintegrate, had, through fortunate foresight and mature determination escaped potential disaster, and had found himself, essentially alone, in New York City. That was April 1939. Within 5 years, his early studies completed and military service over, his future had been established with crystallography, and even more particularly, that aspect of it which was related to the “pathology” of metals. He was to establish one of the first laboratories devoted to research of lattice defects and to lay the groundwork for what is now known as Materials Science. Contemporaneous with the operation of this laboratory and as an outgrowth of his own basic connection with the famous “Brooklyn Poly,” Weissmann included, among his manifold teaching, research, and consulting activities, the acceptance of a position as an editor of the Powder Diffraction File, the PDF. The PDF was then just large enough, just important enough and had just that suggestion of an important reach into the future to necessitate an equally important attention from a group of persons schooled and skilled in the most recent techniques of X-ray powder diffraction. Weissmann (metals), Ben Post (organics), of the Brooklyn Polytechnic Institute and J. V. Smith (minerals) (University of Chicago) were the first thus crystographically trained persons to oversee the PDF.
Crystal data and powder diffraction data for p-lodotoluene at 293 K
Authors: Álvarez-Larena A. , Estop E. , Rodríguez-Romero J. , Tauler E. , Alcobé X.
Published: January 2013

The powder diffraction pattern for p-Iodotoluene C7H7I at 293 K (P212121, No. 19, Z = 4) is given. The cell parameters found are a = 16.484(2) Å, b = 7.444(2) Å, c = 6.108(l) Å.
Crystal structure of a new compound Li2Mg2(WO4)3
Authors: Fu Zhengmin , Li Wenxiu
Published: January 2013

The crystal structure of a new compound Li2Mg2(WO4)3 has been determined by means of X-ray powder diffraction. Li2Mg2(WO4)3 belongs to the orthorhombic system, with space group Pnma and the lattice parameters are: a = 5.1129 Å, b = 10.462 A, and c = 17.612 Å at room.temperature. Its measured density is Dm = 5.48 g/cm3, and each unit cell contains four formula weights.
Accurate fully automated powder diffraction data using zero-background sample holders
Authors: Misture S. T. , Chatfield L. R. , Snyder R. L.
Published: January 2013

An increasingly frequent used sample holder, the zero-background holder (ZBH), is evaluated for use in external standard calibration of powder patterns. The effectiveness of the ZBH calibration method is determined by comparison to the conventional internal- and external-standard calibration techniques. The three calibration methods are compared using the results of lattice parameter refinements of test powders, using Si as the standard. Several test materials were used in the evaluation which cover a wide range of absorption coefficients so sample transparency effects can be distinguished from sample displacement effects. Results of the calibrations clearly indicate that the ZBH method gives precision and accuracy comparable to the internal-standard method, and significantly better than the external-standard technique. In addition, the ZBH method yields substantially better results than the internal-standard method for materials with low absorption coefficients. Low-angle calibrations are also made on a ZBH using a proposed standard, silver behenate, which has peaks from 1.5° to 20° 2θ. These calibrations have shown that if care is not taken to establish a monolayer of powder on the ZBH crystal, significant errors in refined lattice parameters will result.
The structure characteristics of the diluted magnetic semiconductor Y2−xDyxO3
Authors: Antic B. , Önnerud P. , Rodic D. , Tellgren R.
Published: January 2013

The solid solutions Y2−xDyxO3 (x=0.20,0.50,0.74,1.40,1.80) were obtained by ceramic technology. The crystal structures were refined from X-ray and neutron diffraction data measurements in the cubic space group Ia3 by the Rietveld method. The unit cell dimensions varied from 10.6056(4) Å to 10.6624(1) Å. The structure characteristics were analyzed in relation to the concentration of the magnetic ion. The selected cation–anion–cation bonds, important for the understanding of the superexchange interaction and the magnetic properties, are given. In all samples the Dy3+ ions are randomly distributed in the cation sites 8(b) and 24(d). Comparing the random cation distribution in Y2−xDyxO3 and the preferential distribution in Y2−xGdxO3, it has been concluded that the type of distribution depends on the difference of the lattice constants between RE2O3 and Y2O3. Hence, in this cubic Mn2O3-type of structure, a preferential distribution can be expected in Y2−xNdxO3, Y2−xSmxO3, Y2−xEuxO3, Y2−xLuxO3, and a random distribution in Y2−xHoxO3.
X-ray powder diffraction data for chioroquine sulphate monohydrate, C18H26CIN3·H2SO4·H2O
Authors: Rendle D. F. , Cain P. M.
Published: January 2013

X-ray powder diffraction data for chioroquine sulphate monohydrate [7—chloro—4—(4—diethylamino—1—methylbutylamino)—quinoline sulphate monohydrate, C18H26C1N3· H2SO4 · H2O] have been determined. Crystals of chioroquine sulphate monohydrate are orthorhombic, space group P212121 with a=9.0134(7), b=11.7417(6), c= 19.850(1) Å, Z=4, and Dx= 1.378 g cm−3. The F30 index is 121 (0.0062, 40).
X-ray powder diffraction patterns of energetic materials
Authors: Sullenger D. B. , Cantrell J. S. , Beiter T. A.
Published: January 2013

X-ray powder diffraction patterns for 18 phases of 14 well-known explosives have been developed in our laboratory. Experimental patterns were obtained with an automated diffractometer for those phases for which samples were available. For phases with known crystal structures, patterns were calculated from the lattice and atomic positional parameters for comparison with the experimental patterns. Eleven of the experimental patterns have been included in Powder Diffraction File (PDF) Sets 40 and 42; four have been accepted but not yet issued. A final experimental pattern shall be submitted this year. In two other instances, since samples of sufficient quantity and/or quality were not available, calculated patterns alone are considered here. A review of the development of the crystallographic knowledge of these substances is given here together with a critique of the patterns and other known patterns of these phases.
X-ray powder data for synthetic dolerophanite, copper(II) oxysulphate [Cu2O(SO4)]
Authors: Ginting A. R. , O'Connor B. H. , Dunn J. G.
Published: January 2013

Bragg–Brentano X-ray powder diffractometry data and refined unit cell parameters are reported for a synthetic sample of dolerophanite, copper (II) oxysulphate [Cu2O(SO4)], prepared by heating AR copper (II) sulphate anhydrate in a muffle furnace at 725 °C. The data are compared with (i) two Debye–Scherrer patterns published by Mrose [Am. Mineral. 6, 146–153 (1961)]—for a synthetic sample and for a natural dolerophanite, the latter being pattern 13–189 in the ICDD Powder Diffraction File and (ii) a Debye–Scherrer pattern for a synthetic dolerophanite described by Borchardt and Daniels [J. Phys. Chem. 61, 917–921 (1957)]. A calculated pattern is also presented for the crystal structure of dolerophanite described by Effenberger [Monatschefte fur Chemie. 116, 927–931 (1985)]. The measured and calculated patterns reported here show reasonable internal consistency for both line positions and intensity data. While the agreement between these results and the data sets of Mrose is sound in terms of line positions, there is substantial disagreement overall between the intensity values given by the authors and those of Mrose. There is closer agreement between the intensities from the current study and those of Borchardt and Daniels.
Emergency Department Organisation for Disasters: A Review of Emergency Department Disaster Plans in Public Hospitals of Singapore
Authors: Lee Francis Chun Yue , Goh Siang Hiong , Wong Ho Poh , Anantharaman V.
Published: January 2013

Disaster management plans of emergency departments (EDs) in four major public hospitals were reviewed. A comparison was made between these plans, and they were analyzed to gain an understanding of the differing objectives and doctrines behind the practices. These were summarized into five major management concepts, which are considered to be critical to the success of a disaster plan: 1) staff mobilization systems (cascading vs batch mobilization); 2) staff deployment systems; 3) team organization (surgeons vs residents); 4) area management (the role of the area manager); 5) casualty volume management (accommodation vs expansion vs extension concepts). The-concepts derived should serve as a useful guide to the development of an ED disaster plan and potentially influence how new ED facilities could be planned.
The Development and Evaluation of a Paramedic-Staffed Mobile Intensive Care Unit for Interfacility Patient Transport
Authors: Domeier Robert M. , Hill James D. , Simpson Roger D.
Published: January 2013

Objective:

As the role of paramedics evolves, evaluation of their ability to accomplish an expanded scope of practice is necessary. The objective of this study was to determine whether specially trained paramedics can monitor and treat patients appropriately during interfacility transports that traditionally have required the use of supplemental, hospital-based personnel.

Methods:

A paramedic-staffed mobile intensive care unit was developed as a cooperative program between Huron Valley Ambulance and the Washtenaw/Livingston County Medical Control Authority. This prospective observational study involved 111 patients requiring interfacility transport, conveyed by a paramedic-staffed mobile intensive care unit. A change in the Acute Physiologic and Chronic Health Evaluation (APACHE II) score components of mean arterial pressure, heart rate, and respiratory rate at the beginning and end of the transport was used to evaluate the ability of the paramedics to accomplish the transfer appropriately.

Results:

APACHE II scares increased in 20 patients, decreased in 16, and were unchanged in 75. The mean value for the change in APACHE score was 0.11 (95% confidence interval: −0.11−0.33).

Conclusion:

Specially trained paramedics can monitor and treat patients appropriately during interfacility transfers that traditionally would have required supplementation with additional hospital staff.