Update in a Rietveld analysis program for x-ray powder spectro-diffractometry

2003 ◽  
Vol 18 (1) ◽  
pp. 32-35 ◽  
Author(s):  
Yanan Xiao ◽  
Fujio Izumi ◽  
Timothy Graber ◽  
P. James Viccaro ◽  
Dale E. Wittmer

A computer program for refining anomalous scattering factors using x-ray powder diffraction data was revised on the basis of the latest version of a versatile pattern-fitting system, RIETAN-2000. The effectiveness of the resulting program was confirmed by applying it to simulated and measured powder-diffraction patterns of Mn3O4 taken at a synchrotron light source.

1999 ◽  
Vol 14 (2) ◽  
pp. 106-110 ◽  
Author(s):  
Yanan Xiao ◽  
Shinjiro Hayakawa ◽  
Yohichi Gohshi ◽  
Masaharu Oshima ◽  
Fujio Izumi ◽  
...  

In order to exploit X-ray powder spectro-diffractometry, the program RIETAN-97ß for refining crystal structure and lattice parameters by the Rietveld method was modified extensively. The resulting software can be used to refine anomalous scattering factors, fr and fi, for specified crystallographic sites near the X-ray absorption edge of a particular element. The effectiveness of the modified software was tested by using powder diffraction patterns simulated by the original RIETAN-97ß software and a series of measured powder diffraction patterns of Fe3O4 with incident X-ray energies near the absorption edge of iron.


Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 894
Author(s):  
Yana Tzvetanova ◽  
Ognyan Petrov ◽  
Thomas Kerestedjian ◽  
Mihail Tarassov

The Rietveld method using X-ray powder diffraction data was applied to selected skarn samples for quantitative determination of the present minerals. The specimens include garnet, clinopyroxene–garnet, plagioclase–clinopyroxene–wollastonite–garnet, plagioclase–clinopyroxene–wollastonite, plagioclase–clinopyroxene–wollastonite–epidote, and plagioclase–clinopyroxene skarns. The rocks are coarse- to fine-grained and characterized by an uneven distribution of the constituent minerals. The traditional methods for quantitative analysis (point-counting and norm calculations) are not applicable for such inhomogeneous samples containing minerals with highly variable chemical compositions. Up to eight individual mineral phases have been measured in each sample. To obtain the mineral quantities in the skarn rocks preliminary optical microscopy and chemical investigation by electron probe microanalysis (EPMA) were performed for the identification of some starting components for the Rietveld analysis and to make comparison with the Rietveld X-ray powder diffraction results. All of the refinements are acceptable, as can be judged by the standard indices of agreement and by the visual fits of the observed and calculated diffraction profiles. A good correlation between the refined mineral compositions and the data of the EPMA measurements was achieved.


1995 ◽  
Vol 10 (4) ◽  
pp. 296-299 ◽  
Author(s):  
S. T. Misture ◽  
C. Park ◽  
R. L. Snyder ◽  
B. Jobst ◽  
B. Seebacher

Several compositions of the solid solutions (CaxSr1−x)CuO2 and (CaxSr1−x)2CuO3, both of which are found as minor phases in the high-temperature superconductors, were prepared by solid-state reaction. X-ray powder-diffraction patterns for three compositions of (CaxSr1−x)CuO2 and two for (CaxSr1−x)2CuO3 are presented.


2013 ◽  
Vol 46 (3) ◽  
pp. 649-655 ◽  
Author(s):  
Sachiko Maki ◽  
Eiji Nishibori ◽  
Daisuke Kawaguchi ◽  
Makoto Sakata ◽  
Masaki Takata ◽  
...  

An algorithm for determining the element-selective charge density has been developed using the maximum entropy method (MEM), Rietveld analysis and synchrotron X-ray multi-wavelength anomalous powder diffraction data. This article describes in detail both experimental and analytical aspects of the developed method. A structural study of yttrium mono-metallofullerene, Y@C82, 1:1 co-crystallized with toluene using the present technique is reported in order to demonstrate the applicability of the method even when only medium resolution data are available (d> 1.32 Å). Element-selective MEM charge density maps, computed from synchrotron X-ray powder diffraction data collected at three distinct wavelengths around the yttriumK-absorption edge (∼0.727 A), are employed for determining three crystallographic sites of the disordered yttrium.


1997 ◽  
Vol 12 (3) ◽  
pp. 134-135
Author(s):  
Liangqin Nong ◽  
Lingmin Zeng ◽  
Jianmin Hao

The compound DyNiSn has been studied by X-ray powder diffraction. The X-ray diffraction patterns for this compound at room temperature are reported. DyNiSn is orthorhombic with lattice parameters a=7.1018(1) Å, b=7.6599(2) Å, c=4.4461(2) Å, space group Pna21 and 4 formula units of DyNiSn in unit cell. The Smith and Snyder Figure-of-Merit F30 for this powder pattern is 26.7(0.0178,63).


2016 ◽  
Vol 850 ◽  
pp. 3-7
Author(s):  
Shu Hui Liu ◽  
Liu Qing Liang ◽  
Chang Sheng Qin ◽  
De Gui Li ◽  
Ling Min Zeng ◽  
...  

Rare earth-transition metal (R-T) intermetallics have been well used because of their excellent properties. The X-ray diffraction patterns of many new phases in the R-T system have not been extensively studied. A new compound AlCrNi3Pr was prepared by arc melting using non-consumable tungsten electrode under argon atmosphere, and then annealed at 1023K for 30 days. The X-ray powder diffraction data of AlCrNi3Pr was collected on a Rigaku SmartLab X-ray powder diffractometer. The powder patterns of the compound were indexed, and the structure refinement by using Rietveld method indicated that the AlCrNi3Pr compound crystallized in the hexagonal structure, space group P6/mmm (No.191) with PrNi5 structure type, a=b=5.0553(9) Ǻ, c=4.0763(6) Ǻ, V=90.22Ǻ3, Z=1, ρx=7.288g cm-3, the Smith–Snyder FOM F30=279.1(0.0044, 32) and the intensity ratio RIR=1.23.


1999 ◽  
Vol 14 (4) ◽  
pp. 280-283 ◽  
Author(s):  
A. Rafalska-Łasocha ◽  
W. Łasocha ◽  
M. Michalec

The X-ray powder diffraction patterns of anilinium trimolybdate tetrahydrate, (C6H5NH3)2Mo3O10·4H2O, and anilinium trimolybdate dihyhydrate, (C6H5NH3)2Mo3O10·2H2O, have been measured in room temperature. The unit cell parameters were refined to a=11.0670(7) Å, b=7.6116(8) Å, c=25.554(3) Å, space group Pnma(62) and a=17.560(2) Å, b=7.5621(6) Å, c=16.284(2) Å, β=108.54(1)°, space group P21(4) or P21/m(11) for orthorhombic anilinium trimolybdate tetrahydrate and monoclinic anilinium trimolybdate dihydrate, respectively.


1991 ◽  
Vol 6 (2) ◽  
pp. 107-110
Author(s):  
Markus Garsche ◽  
Ekkehart Tillmanns ◽  
Thomas Bauer ◽  
Reinhard X. Fischer ◽  
Ladislav Bohaty

AbstractSix 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 Rb2C4H4O6 and Ca [Sb2{C4H2O6}2]·2H2O are given.


2009 ◽  
Vol 65 (6) ◽  
pp. i44-i44 ◽  
Author(s):  
Zhen-Hua Liang ◽  
Kai-Bin Tang ◽  
Qian-Wang Chen ◽  
Hua-Gui Zheng

Rubidium dicalcium triniobate(V), RbCa2Nb3O10, has been synthesized by solid-state reaction and its crystal structure refined from X-ray powder diffraction data using Rietveld analysis. The compound is a three-layer perovskite Dion–Jacobson phase with the perovskite-like slabs derived by termination of the three-dimensional CaNbO3perovskite structure along theabplane. The rubidium ions (4/mmmsymmetry) are located in the interstitial space.


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