X-Ray Analysis of the New Ferrites CuCr2-xFexSe4

2010 ◽  
Vol 163 ◽  
pp. 217-220
Author(s):  
Ewa Maciążek ◽  
Grzegorz Dercz ◽  
Izabela Jendrzejewska ◽  
Tomasz Goryczka ◽  
Rafał Sitko
Keyword(s):  
Structure Determination ◽  
Spinel Structure ◽  
Rietveld Method ◽  
Structure Refinement ◽  
X Ray ◽  
Normal Spinel ◽  
Multi Phase ◽  
Sintering Method

The series of ferrites CuCr2-xFexSe4 (x=0.10.5) were obtained as polycrystalline compounds using conventional ceramics sintering method. The stoichiometric amounts of spectrally pure elements were used for synthesis. The phase and structure determination was done using X-ray analysis. The Rietveld method was applied for structure refinement. It occurred that all samples were multi-phase, the main content crystallized in cubic, normal spinel structure.

X-Ray Analysis of the Cd0.5Ge0.5Cr2Se4 and CdCr1.9Ge0.075Se4 Compounds

2007 ◽  
Vol 130 ◽  
pp. 93-96
Author(s):  
Ewa Maciążek ◽  
Tomasz Goryczka ◽  
Izabela Jendrzejewska
Keyword(s):  
Structure Analysis ◽  
Spinel Structure ◽  
Rietveld Method ◽  
Spinel Phase ◽  
Structure Refinement ◽  
Ceramic Method ◽  
X Ray ◽  
Normal Spinel

The polycrystalline Cd0.5Ge0.5Cr2Se4 and CdCr1.9Ge0.075Se4 compounds were obtained using ceramic method. X-ray analysis was used to make phase and structure analysis. The Rietveld method was applied for structure refinement. Both compounds crystallized in cubic, normal spinel structure, Fd 3m. Besides the main spinel phase, Cr2Se3 was observed.

Rietveld refinement of the solid-solution series: (Cu,Mg)SO4·H2O

1995 ◽  
Vol 10 (3) ◽  
pp. 189-194 ◽  
Author(s):  
C. L. Lengauer ◽  
G. Giester
Keyword(s):  
Solid Solution ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Solid Solution Series ◽  
Cation Site ◽  
Tg Analysis ◽  
X Ray ◽  
Solution Series

The kieserite-type solid-solution series of synthetic (Cu,Mg)SO4·H2O was investigated by TG-analysis and X-ray powder diffraction using the Rietveld method. Representatives with Cu≥20 mol% are triclinic distorted () analogous to the poitevinite (Cu,Fe)SO4·H2O compounds. Cation site ordering with preference of Cu for the more distorted M1 site was additionally proven by the structure refinement.

Crystal structure of potassium tetraperoxomolybdate (VI) K2[Mo(O2)4]

2005 ◽  
Vol 20 (3) ◽  
pp. 203-206 ◽  
Author(s):  
M. Grzywa ◽  
M. Różycka ◽  
W. Łasocha
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters

Potassium tetraperoxomolybdate (VI) K2[Mo(O2)4] was prepared, and its X-ray powder diffraction pattern was recorded at low temperature (258 K). The unit cell parameters were refined to a=10.7891(2) Å, α=64.925(3)°, space group R−3c (167), Z=6. The compound is isostructural with potassium tetraperoxotungstate (VI) K2[W(O2)4] (Stomberg, 1988). The sample of K2[Mo(O2)4] was characterized by analytical investigations, and the results of crystal structure refinement by Rietveld method are presented; final RP and RWP are 9.79% and 12.37%, respectively.

Laboratory X-ray powder diffraction: a comparison of different geometries with special attention to the usage of the CuKα doublet

1999 ◽  
Vol 32 (4) ◽  
pp. 799-807 ◽  
Author(s):  
Martin Oetzel ◽  
Gernot Heger
Keyword(s):  
Powder Diffraction ◽  
Profile Analysis ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Strong Dependence ◽  
Line Profile Analysis ◽  
X Ray ◽  
Diffraction Angle ◽  
Maximum Parameters ◽  
The Right

In a laboratory X-ray powder diffraction study, the evaluation of the patterns of three Bragg–Brentano powder diffractometers with different monochromator geometries has been undertaken. For the measurements on each diffractometer, the standard reference material SRM 640 (silicon) and the corundum samples SRM 674a and SRM 1976 have been used. In each case, the peak profiles were fitted with a split Pearson VII function and the FWHM (full width at half-maximum) parameters and exponentmwere determined for the left (lower 2θ) and the right (higher 2θ) sides of the Bragg peaks. It was found that there is a strong dependence of both the FWHM and the exponentmon the diffraction angle for the two configurations that included monochromators, whereas nearly constant values ofmwere found for the geometrically simplest diffractometer working without a monochromator. Finally, the two components of the CuKα doublet show systematically different peak profiles. There is a clear difference not only concerning the FWHM, which becomes more obvious at higher 2θ values, but also in the course ofmwith respect to the diffraction angle for the left and the right tails of the powder reflections. This is the main reason for the difficulties inKα2stripping and also in single-line-profile analysis when using theKα doublet. Therefore, it is not surprising that this phenomenon, which can be explained by Heisenberg's uncertainty principle, does affect the reliability (represented by standardRvalues) of structure refinement by the Rietveld method.

Structure Refinement of High-Density Polyethylene Using X-Ray Powder Diffraction Data and the Rietveld Method

1995 ◽  
Vol 39 ◽  
pp. 515-521
Author(s):  
Kenneth B. Schwartz ◽  
Robert B. Von Dreele
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
High Density Polyethylene ◽  
Rietveld Method ◽  
Structure Refinement ◽  
High Density ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Voigt Profile ◽  
Full Structure

A full structure analysis of a completely crystallized sample of high-density polyethylene (HDPE) has been achieved using x-ray powder diffraction data collected on a laboratory-based powder diffractometer. The structure refinement is performed using the Rietveld method and includes refinement of the carbon and hydrogen atomic positions and temperature factors. The C-C and C-H bond distances and the C-C-C bond angle along the polyethylene chain have been calculated from the refined atomic positions and are in very good agreement with previous experimental and modelling determinations. Evaluations of the pseudo-Voigt profile parameters for Lorentzian strain broadening and me Scherrer coefficient for Gaussian broadening yield reasonable values for microstrain and particle size for this sample. Refinement of the preferred orientation parameter indicates that the HDPE flakes consist of platy crystals or lamellae that are packed normal to the diffraction vector.

X-Ray Powder Diffraction Data and Crystal Refinement of Ternary Compound Ti4ZrSi3

2020 ◽  
Vol 841 ◽  
pp. 99-102
Author(s):  
Liu Qing Liang ◽  
Yan Ying Wei ◽  
De Gui Li
Keyword(s):  
Ternary Compound ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Structure Type ◽  
Hexagonal Structure ◽  
Powder Diffraction Data ◽  
Tungsten Electrode ◽  
X Ray

Ternary compound Ti4ZrSi3 was prepared by arc melting using a non-consumable tungsten electrode under argon atmosphere, then annealed at 1023K for 30 days, the X-ray powder diffraction data of Ti4ZrSi3 was collected on a Rigaku SmartLab X-ray powder diffractometer. The powder patterns of the compound were indexed and structure refinement by using Rietveld method indicate that the Ti4ZrSi3 compound crystallizes in the hexagonal structure, space group P6/mcm (No.193) with Mn5Si3 structure type, a=b=7.5759(3) Ǻ, c=5.2162(2) Ǻ, V=259.28Ǻ3, Z=2, ρx=4.779g cm-3, the Smith–Snyder FOM F30=148.7(0.0064, 46) and the intensity ratio RIR=1.37. The Rietveld refinement results were Rp = 0.0836, Rwp= 0.1092.

X-Ray Powder Diffraction Data and Crystal Refinement of a New Compound AlCrNi3Pr

2016 ◽  
Vol 850 ◽  
pp. 3-7
Author(s):  
Shu Hui Liu ◽  
Liu Qing Liang ◽  
Chang Sheng Qin ◽  
De Gui Li ◽  
Ling Min Zeng ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Structure Type ◽  
Hexagonal Structure ◽  
Powder Diffraction Data ◽  
Tungsten Electrode ◽  
X Ray ◽  
Diffraction Patterns

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.

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