Aluminum-Doped Zirconia Nanopowders:  Chemical Vapor Synthesis and Structural Analysis by Rietveld Refinement of X-ray Diffraction Data

2003 ◽  
Vol 15 (13) ◽  
pp. 2668-2674 ◽  
Author(s):  
Vladimir V. Srdić ◽  
Markus Winterer

1996 ◽  
Vol 81 (9-10) ◽  
pp. 1133-1140 ◽  
Author(s):  
Sang-Heon Shim ◽  
Soo Jin Kim ◽  
Jung Ho Ahn


1996 ◽  
Vol 453 ◽  
Author(s):  
H.-C. Zur Loye ◽  
P. Núñez ◽  
M. A. Rzeznik

AbstractThe one-dimensional compounds Sr3MgPtO6, Sr3MgIrO6, Sr3MgRhO6, Sr3GdRhO6, have been synthesized and structurally characterized by Rietveld refinement of powder X-ray diffraction data. All four compounds are isostructural with the rhombohedral K4CdCl6-type structure. The structure consists of infinite one-dimensional chains of alternating face-shared MO6 octahedra (M = Pt, Ir, Rh) and M′O6 (M′ = Gd, Mg) trigonal prisms. The strontium cations are located in a distorted square antiprismatic environment. Magnetic susceptibility data show that both Sr3MgIrO6 and Sr3MgRhO6 obey the Curie-Weiss law with θ = −6(1) K, and θ= −15(3)K, respectively. Sr3GdRhO6 obeys the Curie law with μeff = 7.80 B.M, consistent with an oxidation state of +3 for both rhodium and gadolinium.



Author(s):  
W. A. Crichton ◽  
G. B. M. Vaughan ◽  
M. Mezouar

AbstractThe structure of a 2-chain helical form of sulphur with 9 atoms per unit-cell has been determined from powder synchrotron x-ray diffraction data obtained at 3 GPa and 400ºC, using a combination of global optimization, simulated annealing and Rietveld refinement techniques. Final refinement of the structure in trigonal space group



2015 ◽  
Vol 30 (1) ◽  
pp. 63-66 ◽  
Author(s):  
Chao Zeng ◽  
Guoqiang Lin ◽  
Weijing Zeng ◽  
Wei He

The crystal structure of new Tb3CuAl3Ge2 quaternary compound was studied by the Rietveld method from powder X-ray diffraction (XRD) data. The Tb3CuAl3Ge2 compound crystallized in the hexagonal Y3NiAl3Ge2-type structure with space group P-62m (no. 189) and lattice parameters a = 7.0041(2) Å, c = 4.1775(1) Å, V = 177.48 Å3. There is only one formula in each unit cell, Z = 1, and the density of Tb3CuAl3Ge2 is ρx = 7.1696 g cm−3. The reliability factors characterizing the Rietveld refinement results are Rp = 6.43%, Rwp = 8.65%, RB = 4.81%, and RF = 4.09%, respectively. The powder XRD data of Tb3CuAl3Ge2 were presented and the reliability of indexation is F30 = 120.9(0.0073, 34).



2010 ◽  
Vol 25 (3) ◽  
pp. 253-257 ◽  
Author(s):  
E. J. Friedrich ◽  
R. Fernández-Ruiz ◽  
J. M. Merino ◽  
M. León

X-ray powder diffraction data for CuGa0.15In0.85Se2 and CuGa0.50In0.50Se2 are reported. Indexing of the X-ray diffraction powder pattern and the Rietveld refinement confirmed that these compounds crystallize in the tetragonal crystal system, with space group I-42d (No. 122) and lattice parameters of a=5.7528(2) Å and c=11.5225(3) Å for CuGa0.15In0.85Se2 and a=5.6847(1) Å and c=11.2817(1) Å for CuGa0.50In0.50Se2. The CuGaxIn1−xSe2 system presents the chalcopyrite type crystal structure (CuFeS2) and corresponds to two stacked zinc-blende unit cells. The metal atoms Cu, In, and Ga are regularly ordered in the unit cell. Every Se atom is tetrahedrally bonded to two Cu and two In and Ga atoms.



Author(s):  
Nicolas Massoni ◽  
Ronan Hegron ◽  
Lionel Campayo

Ca2 Ln 8(SiO4)6O2 apatites with Ln = La, Ce, Pr, Nd, Sm, Eu, Gd and Tb crystallize in space group P63/m. The crystal structure of apatite-type Ca2Ce8(SiO4)6O2 [dicalcium octacerium hexakis(silicate) dioxide], which has been synthesized by calcination, was refined from powder X-ray diffraction data using the Rietveld method. A database survey shows that contrary to the previously published Ca2Ce8(SiO4)6O2 structure [Skakle et al. (2000). Powder Diffr. 15, 234–238], the cell volume of the structure reported here is consistent with those of other Ln apatites.



2009 ◽  
Vol 24 (1) ◽  
pp. 41-43 ◽  
Author(s):  
Guilherme Oliveira Siqueira ◽  
Érica Gonçalves Gravina ◽  
Jackson Antônio Lamounier Camargos Resende ◽  
Nelson Gonçalves Fernandes

A natural sodalite from the geological site Alkaline Complex of Floresta Azul, Bahia, Brazil, has been characterized by electron microprobe, infrared spectroscopy, and powder high-resolution X-ray diffraction techniques. The mineral is an aluminosilicate framework, formed by cages called sodalite unity. Although the sample is natural, the chemical analysis reveals that it is indeed the end member sodalite sensu strictu, Na8[Si6Al6O24]Cl2. Infrared spectroscopy shows Si, Al tetrahedral-oxygen stretching nonsymmetric mode, stretching symmetric mode, and bending modes. Indexing of the experimental X-ray diffraction pattern led to cubic space group P-43n, and unit-cell parameters: a=8.8767(7) Å, Dx=2.301 g cm−3, and V=699.46(1) Å3. X-ray diffraction data are reported. Rietveld refinement was also performed, and the confidence factors are Rp=0.079, Rwp=0.118, and χ2=2.19. The structure of the minerals of sodalite group holds four different tetrahedra: AlO4, ClNa4, Na(ClO3), and SiO4, with Al, Cl, Na, and Si located at the center of each tetrahedron.



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