Structure determination and Rietveld refinement of Y0.8Ca0.2Ba1.8La0.2Cu3Oy

2001 ◽  
Vol 16 (4) ◽  
pp. 212-215 ◽  
Author(s):  
X. S. Wu ◽  
F. Z. Wang ◽  
S. S. Jiang

The structure of the new Y0.8Ca0.2Ba1.8La0.2Cu3Oy (YBLCO) compound was obtained at 298 K from X-ray powder diffraction data and refined by the Rietveld technique. YBLCO has a structure isotypical with YBa2Cu3Oy (YBCO) at room temperature. The crystal data are: Y0.81Ca0.19Ba1.8La0.2Cu3O7.08, Mw=657.69, orthorhombic system, space group Pmmm, a=3.8731(1) Å, b=3.8249(1) Å, c=11.6602(3) Å, V=172.740(13) Å3, Z=1, dx=6.325 g/cm3; the structure was refined with 37 parameters to Rwp=7.66%, Rp=5.86%, and Rexp=5.11% for 2001 data points. Moreover, the proportions of Ca and La were refined to be 0.19 and 0.2, in agreement with the stoichiometric proportion of 0.2.

2004 ◽  
Vol 19 (4) ◽  
pp. 329-332
Author(s):  
H. L. Cai ◽  
X. S. Wu ◽  
F. Z. Wang ◽  
A. Hu ◽  
S. S. Jiang ◽  
...  

The crystal structure of La0.67Ca0.33Mn0.80Cu0.20O3 (LCMCO) compound was determined from laboratory X-ray powder diffraction data and refined by the Rietveld method. LCMCO is isostructural with La0.67Ca0.33MnO3 (LCMO). The crystal data are: La0.64Ca0.36Mn0.82Cu0.18O3.01, Mr=843.80, orthorhombic system, space group Pnma, a=5.4364(1) Å, b=7.6725(2) Å, c=5.4452(1) Å, V=227.124(8)Å3, Z=4, Dx=6.168 g∕cm3. In comparing with the Cu-free compound, subtle structural changes such as bond lengths and bond angles found in the Cu-doped compound may be responsible for the larger effects on the transport and magnetic properties when Cu partially substitutes for Mn in CMCO.


1999 ◽  
Vol 14 (4) ◽  
pp. 284-288 ◽  
Author(s):  
Hoong-Kun Fun ◽  
Ping Yang ◽  
Minoru Sasaki ◽  
Masasi Inoue ◽  
Hideoki Kadomatsu

The crystal structure of γ-Mo4O11 was obtained at room temperature (296 K) by Rietveld analysis with X-ray powder diffraction data. The crystal belongs to orthorhombic system, space group: Pna21, Z=4, Mr=559.753 (Atomic weights 1977), Dx=4.1228 g/cm3, F(000)=1024.0, μ=451.293 cm−1 (Int. Tab. Vol. C, Table 4.2.4.2, p. 193, λ=1.540 60 Å), a=24.4756(5) Å, b=6.7516(1) Å, c=5.4572(1) Å, and V=901.80(3) Å3. The structure was refined to Rwp=5.60%, Rp=4.27%, Rb=3.36%, and Rf=2.74% for 65 parameters with 3541 step intensities and 3055 peaks. Goodness of the fit S=3.35.


Author(s):  
Robert E. Dinnebier ◽  
Hanne Nuss ◽  
Martin Jansen

AbstractThe crystal structures of solvent-free lithium, sodium, rubidium, and cesium squarates have been determined from high resolution synchrotron and X-ray laboratory powder patterns. Crystallographic data at room temperature of Li


1996 ◽  
Vol 11 (4) ◽  
pp. 301-304
Author(s):  
Héctor Novoa de Armas ◽  
Rolando González Hernández ◽  
José Antonio Henao Martínez ◽  
Ramón Poméz Hernández

p-nitrophenol, C6H5NO3, and disophenol, C6H3I2NO3, have been investigated by means of X-ray powder diffraction. The unit cell dimensions were determined from diffractometer methods, using monochromatic CuKα1 radiation, and evaluated by indexing programs. The monoclinic cell found for p-nitrophenol was a=6.159(2) Å, b=8.890(2) Å, c=11.770(2) Å, β=103.04(2)°, Z=4, space group P21 or P2l/m, Dx=1.469 Mg/m3. The monoclinic cell found for disophenol has the dimensions a=8.886(1) Å, b=14.088(2) Å, c=8.521(1) Å, β=91.11(1)°, Z=4, space group P2, P2, Pm or P2/m, Dx=2.438 Mg/m3.


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