Interaction of the Components in the {Ce, Gd}-{Ti, Zr}-Sb Systems

2019 ◽  
Vol 289 ◽  
pp. 3-11
Author(s):  
Oleksandr Senchuk ◽  
Roman E. Gladyshevskii
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Ternary Systems ◽  
The Other ◽  
Powder Diffraction Data ◽  
Isothermal Sections ◽  
X Ray ◽  
Ternary Compounds ◽  
New Compounds

The phase equilibria in the ternary systems {Ce, Gd}–{Ti, Zr}–Sb were investigated by means of X-ray powder diffraction and energy-dispersive X-ray spectroscopy. The isothermal sections of the phase diagrams at 600°C were constructed. The formation of three ternary compounds (Ce2Ti7Sb12, Ce3TiSb5, and Gd2Ti11Sb14) was confirmed in the {Ce, Gd}–Ti–Sb systems and no more ternaries were found. The investigation of the {Ce, Gd}–Zr–Sb systems revealed several new ternary compounds and confirmed the known ones. The crystal structure of the new compound Ce0.08(3)Zr1.92(3)Sb was determined from X-ray powder diffraction data. The other new compounds in the Ce–Zr–Sb system were found to have compositions close to ~CeZrSb4and ~Ce2Zr3Sb5. In the Gd–Zr–Sb system the existence of a large homogeneity range was established for the GdZrSb compound along the isoconcentrate 33.3 at.% Sb: Gd1-xZr1+xSb (x= 00.905(18) at 600°C), and a new compound, ~Gd3Zr3Sb14, was discovered. The crystal structures at the boundary compositions of the Gd1-xZr1+xSb phase were refined from X-ray powder diffraction data.

Crystallographic study of ternary ordered skutterudite IrGe1.5Se1.5

2010 ◽  
Vol 25 (3) ◽  
pp. 247-252 ◽  
Author(s):  
F. Laufek ◽  
J. Návrátil
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Crystallographic Data ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Crystallographic Study ◽  
Related Phase ◽  
The Ideal

The crystal structure of skutterudite-related phase IrGe1.5Se1.5 has been refined by the Rietveld method from laboratory X-ray powder diffraction data. Refined crystallographic data for IrGe1.5Se1.5 are a=12.0890(2) Å, c=14.8796(3) Å, V=1883.23(6) Å3, space group R3 (No. 148), Z=24, and Dc=8.87 g/cm3. Its crystal structure can be derived from the ideal skutterudite structure (CoAs3), where Se and Ge atoms are ordered in layers perpendicular to the [111] direction of the original skutterudite cell. Weak distortions of the anion and cation sublattices were also observed.

Preparation and crystal structure of garnet-type calcium zirconium germanate Ca4ZrGe3O12

2016 ◽  
Vol 31 (4) ◽  
pp. 292-294 ◽  
Author(s):  
V. D. Zhuravlev ◽  
A. P. Tyutyunnik ◽  
N. I. Lobachevskaya
Keyword(s):  
Crystal Structure ◽  
Unit Cell Parameter ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Cell Parameter ◽  
Polycrystalline Sample ◽  
Structural Formula ◽  
Powder Diffraction Data ◽  
Structural Refinement ◽  
X Ray

A polycrystalline sample of Ca4ZrGe3O12 was synthesized using the nitrate–citrate method and heated at 850–1100 °C. Structural refinement based on X-ray powder diffraction data showed that the crystal structure is of the garnet type with a cubic unit-cell parameter [a = 12.71299(3) Å] and the space group Ia$\bar 3$d. The structural formula is presented as Ca3[CaZr]octa[Ge]tetraO12.

scholarly journals Island model with genetic algorithm for solution of crystal structure from X-ray powder diffraction data

2019 ◽  
Vol 537 ◽  
pp. 022002 ◽  
Author(s):  
Aleksandr N Zaloga ◽  
Sergey V Burakov ◽  
Igor S Yakimov ◽  
Konstantin A Gusev ◽  
Petr S Dubinin
Keyword(s):  
Crystal Structure ◽  
Genetic Algorithm ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Island Model ◽  
Powder Diffraction Data ◽  
X Ray

scholarly journals Pressing the Limits of Rietveld Refinement

1988 ◽  
Vol 41 (2) ◽  
pp. 297 ◽  
Author(s):  
RA Young
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Structure Refinement ◽  
Site Occupancy ◽  
The Other ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Neutron Powder Diffraction Data ◽  
Refinement Method

Two examples are given, one with X-ray data and one with netltron data, of the determination of structural detail which appear to be at the edge of current possibility for the Rietveld structure-refinement method. In the first example, 2�2 wt% Sb substituted in CalO(P04)6F2 was located. X-ray powder diffraction data collected with special attention to intensity precision and scale constancy were used. The problem was solved through comparison of intra-sample site-occupancy ratios between Sb-doped and undoped samples. In the second example, high quality, high resolution neutron powder diffraction data were required. The problem was to distinguish between two subtly different models of kaolinite for which the R-weighted-pattern values differed only by 2 or 3 units in the third digit and, particularly, to understand the basis for the consistent programmatic choice of one of the models (PI) over the other. The answer was found in the calculated and 'observed' intensities for (h+ k)-odd reflections; although they were very small, less than 1% of the intensities of the main reflections, many of them were distinctly nonzero. Even though these reflections were not separately observable, because of overlap and small size, they nonetheless correlated with one model sufficiently better than the other to produce the consistent choice.

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