Automatic Densitometer Measurements of Powder Diffraction Photographs.

Malmros, Gunnar; Werner, Per‐Erik; Hebrew, C.; Buren, Charles T. Van; Klæboe, P.; Swahn, Carl‐Gunnar

doi:10.3891/acta.chem.scand.27-0493

Cited by 63 publications

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“…There is also a widespread need for experimental techniques for performing structural studies where single-phase powder cannot be obtained. It is clear that the full-profile analysis procedure of Rietveld (1969) can find an application in both fields; particularly the technique as applied to microdensitometermeasured Guinier-H~igg X-ray powder film data (Malmros & Werner, 1973;Malmros & Thomas, 1977;Berg & Werner, 1977). The latter method has the great advantage that it requires extremely small amounts of powder (down to 0-2 mg) and, in as much as it takes full account of overlap, it makes optimal use of the data available.…”

Section: Introductionmentioning

confidence: 99%

Quantitative analysis of multicomponent powders by full-profile refinement of Guinier–Hägg X-ray film data

Werner¹,

Salomé²,

Malmros³

1979

J Appl Cryst

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Full-profile analysis of microdensitometer-measured Guinier-H~igg X-ray powder film data (strictly monochromatized Cu K~I radiation) [see Malmros & Thomas (1977). J. Appl. Cryst. 10,[7][8][9][10][11] is here extended to treat a multicomponent system where two of the components are refinable. The method is demonstrated for the case of: (a) ~-Bi203/KC1 (standard), and (b) CaF2/SiO2 (s-quartz) together with a Mg(OH)2 matrix. In (a), a weight ratio BizO3/KCI of 1:1 gave an experimental result of 0-96(9):1. In (b), a number of admixtures have been studied in the range 1-60 wt% SiO2 all with 10 wt % CaF2. The agreement between weight ratios and profile refinement results suggests that the formal temperature factors function as effective absorption correction parameters. It is thus shown that approximate quantitative analysis is feasible from Guinier-H~igg diffraction data without any previously determined calibration curve. Moreover, the method permits the use of all available overlapping data in the refinement of a structure without needing to exclude data from known impurities [see Waltersson, Werner & Wilhelmi (1977). Cryst. Struct. Commun. 6,[231][232][233][234][235].This feature is likely to prove the most common application of the method.

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Section: Introductionmentioning

confidence: 99%

Quantitative analysis of multicomponent powders by full-profile refinement of Guinier–Hägg X-ray film data

Werner¹,

Salomé²,

Malmros³

1979

J Appl Cryst

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“…This method is particularly appropriate for small samples. The di¡raction patterns were recorded on ¢lms, visually examined and read by an LS20 optical densitometer (Malmros and Werner, 1973;Johansson et al, 1980). Identi¢cations of the phases were made using the DIFFRAC-AT (Nusinovici and Winter, 1994) program including the ICDD Powder Di¡raction Data Base, ASTM ¢les 24-0027 and 41-1475 were used to identify calcite and aragonite respectively.…”

Section: X-ray Di¡ractionmentioning

confidence: 99%

Crystallographic and chemical composition of otoconia in the salamander Pleurodeles waltl

Oukda¹,

François²,

Membre³

et al. 1999

Hearing Research

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The aim of the present study was to define the morphology and the crystallographic and chemical composition of otoconia in different regions of the inner ear in Pleurodeles waltl (urodele amphibian). The inner ear of adults was microdissected and otoconia were analyzed by scanning electron microscopy (SEM), X-ray diffraction, energy dispersive X-ray (EDX) and transmission electron microscopy. Two types of crystals were detected by SEM. Otoconia had different shapes depending on their location in the membranous labyrinth. One type had a cylindrical body with a triplanar smooth facet at each end, the other ones had either a prismatic shape with flat sides and end faces or a fusiform shape with rounded body and pointed end. The forms corresponded to those previously identified by other authors. These two types of otoconia had different X-ray diffraction patterns. The cylindrical otoconia were calcitic and located in the utricle, the other ones were aragonitic and located in the saccule, lagena and endolymphatic sac. An analysis by EDX indicated that both types of otoconia contained about 95% calcium with trace quantities of sodium, magnesium, phosphorus, sulfur, chlorine and potassium. Trace amounts of strontium was only found in the aragonitic otoconia. ß 1999 Elsevier Science B.V. All rights reserved.

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“…peak positions, integrated intensities and step-scan intensities were extracted from the powder photograph. This was performed by using an extended version of the drum film scanner system described by MALMROS and WERNER (1973 …”

Section: Data Collectionmentioning

confidence: 99%

On the use of Guinier-Hägg film data for structure analysis The crystal structure of tetraammonium ɑɑ'-μ-oxobis- {[gied'-μ3(S)-malato-O(1),O(2),O(4),0(4')]-di-μ-oxobis[dioxo-molybdate(VI)]} monohydrate

Berg¹,

Werner²

1977

Zeitschrift Für Kristallographie - Crystalline Materials

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AuszugAus den Informationen, die in einer Guinier-Hägg-Pulveraufnahme enthalten sind, wurde die Struktur der nur in mikrokristalliner Form erhältlichen Verbindung (NH^QMoOz^Os] (C4H3C>5)2 · H2O ermittelt und bis zu einer Genauigkeit mäßigen Grades verfeinert. Das dabei angewandte Verfahren umfaßte: Messung der Intensitätsprofile durch schrittweises Abtasten, Indizierung mit Hilfe eines "Ver8ueh-und-Irrtum"-Programmes, Bestimmung der Mo-Lagen aus einer unvollständigen Patterson-Funktion auf der Grundlage von integralen Intensitäten und schließlich die Lokalisierung der leichten Atome, mit Ausnahme des Wasserstoffs, und die Struktur-Verfeinerung durch eine Reihe von Fourier-Rechnungen und Profilanalysen.Die Verbindung hat die Raumgruppe C 2 mit a = 14,572(2) A, b = 10,114(2) Ä, c = 11,461(2)1, β = 121,45(1)°; Ζ = 2. Obwohl die Struktur 51 Parameter aufweist und daher für die Atomkoordinaten nur Näherungswerte erhalten werden konnten, ließ sie sich in ihren Grundzügen feststellen. Sie enthält diskrete Ionen [(Mo02)403(C4H3C>5)2] 4~ mit einer zweizähligen Achse durch ein Ο-Atom. AbstractFrom the information contained in one powder photograph obtained in a Guinier-Hägg camera the crystal structure of (ΝΗι)4[(Μοθ2)ιθ3] (CUHgOsh · H2O, only known in microcrystalline form, has been determined and refined to a moderate degree of accuracy. The work has comprised step-scanning measurement of the intensity profile, indexing with a trial-and-error program, determination of the Mo positions from an incomplete Patterson function derived from resolved integrated intensities, and finally localization of light Brought to you by | New York University Bobst Library Technical Service Authenticated Download Date | 7/25/15 10:31 PM On the use of Guinier-Hägg film data for structure analysis 311 non-hydrogen atoms and structure refinement by a series of Fourier calculations and profile analyses.The material crystallizes in the monoclinic system, space group C 2, with two formula units in a cell of dimensions a = 14.572(2) A, b = 10.114(2) Ä, c = 11.461(2) Ä and β = 121.45(1)°. Since as many as 51 parameters are involved the atomic coordinates obtained are approximate, but the main features of the structure are established. The structure contains discrete [(MoC^UOa (CiHaOs^] 4-ions having a twofold axis through an oxygen atom.

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Automatic Densitometer Measurements of Powder Diffraction Photographs.

Cited by 63 publications

References 0 publications

Quantitative analysis of multicomponent powders by full-profile refinement of Guinier–Hägg X-ray film data

Quantitative analysis of multicomponent powders by full-profile refinement of Guinier–Hägg X-ray film data

Crystallographic and chemical composition of otoconia in the salamander Pleurodeles waltl

On the use of Guinier-Hägg film data for structure analysis The crystal structure of tetraammonium ɑɑ'-μ-oxobis- {[gied'-μ3(S)-malato-O(1),O(2),O(4),0(4')]-di-μ-oxobis[dioxo-molybdate(VI)]} monohydrate

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