Cristobalite-Related Phases in the NaAlO2–NaAlSiO4 System. I. Two Tetragonal and Two Orthorhombic Structures

1998 ◽  
Vol 54 (5) ◽  
pp. 531-546 ◽  
Author(s):  
J. G. Thompson ◽  
R. L. Withers ◽  
A. Melnitchenko ◽  
S. R. Palethorpe
Keyword(s):  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Structure Type ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Modulation Wave ◽  
Wave Approach ◽  
The Ideal

The crystal structures of five new cristobalite-related sodium aluminosilicates with four different structure types from the system Na2−x Al2−x Si x O4, 0 ≤ x ≤ 1 [Na1.95Al1.95Si0.05O4, P41212, a = 5.2997 (6), c = 7.0758 (9) Å; Na1.75Al1.75Si0.25O4, Pbca, a = 10.4221 (11), b = 14.264 (3), c = 5.2110 (5) Å; Na1.65Al1.65Si0.35O4, P41212, a = 10.3872 (7), c = 7.1589 (8) Å; Na1.55Al1.55Si0.45O4, Pbca, a = 10.385 (1), b = 14.198 (3), c = 5.1925 (6) Å; Na1.15Al1.15Si0.85O4, Pb21 a, a = 10.214 (2), b = 14.226 (7), c = 10.308 (1) Å], have been refined by the Rietveld method from X-ray powder diffraction data. Plausible starting models were derived for the x = 0.05, 0.25 and 0.45 structures by analogy. Starting models for the x = 0.35 and 0.85 structures, with previously unreported structure types, were derived from a modulation wave approach based on distortion of the ideal C9 structure type and assuming regular SiO4 and AlO4 tetrahedra.

A Modulation Wave Approach to the Structural Characterization of Three New Cristobalite-Related Sodium Magnesiosilicates

1997 ◽  
Vol 53 (2) ◽  
pp. 203-220 ◽  
Author(s):  
R. L. Withers ◽  
C. Lobo ◽  
J. G. Thompson ◽  
S. Schmid ◽  
R. Stranger
Keyword(s):  
Powder Diffraction ◽  
Structural Characterization ◽  
Diffraction Data ◽  
Structure Type ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Modulation Wave ◽  
Wave Approach ◽  
The Ideal

The crystal structures of three new cristobalite-related sodium magnesiosilicates [Na2MgSiO4, M r = 162.37, orthorhombic, Pna21, a = 10.835 (5), b = 5.279 (12), c = 7.067 (8) Å, D x = 2.668 g cm−3, Z = 4, Cu Kα, λ = 1.5418 Å, μ = 75.96 cm−l, F(000) = 319.87; Na1.74Mg0.79Al0.15Si1.06O4, M r = 157.02, orthorhombic, Pbca, a = 10.487 (7), b = 14.351 (4), c = 5.243 (6) Å, D x = 2.643 g cm−3, Z = 8, Cu Kα, λ = 1.5418 Å, μ = 76.70 cm−l, F(000) = 619.04; Na1.8Mg0.9Si1.1O4, M r = 158.15, tetragonal, P41212, a = 5.330 (6), c = 7.086 (5) Å, D x = 2.609 g cm−3, Z = 2, Cu Kα, λ= 1.5418 Å, μ = 75.44 cm−l, F(000) = 155.94] are determined by Rietveld refinement from X-ray powder diffraction data. Plausible starting models were derived from a modulation wave approach based on the ideal C9 structure type and assuming regular SiO4 and MgO4 tetrahedra.

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.

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.

Structures of four polymorphs of the pesticide dithianon solved from X-ray powder diffraction data

2012 ◽  
Vol 68 (6) ◽  
pp. 661-666 ◽  
Author(s):  
Ivan Halasz ◽  
Robert Dinnebier ◽  
Tiziana Chiodo ◽  
Heidi Saxell
Keyword(s):  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Weak Interactions ◽  
Rietveld Method ◽  
Carbonyl Groups ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Space Groups

The crystal structures of four polymorphs of the pesticide dithianon (5,10-dihydro-5,10-dioxonaphtho[2,3-b]-1,4-dithiine-2,3-dicarbonitrile) have been solved from powder diffraction data and refined using the Rietveld method. Three polymorphs crystallize in non-centrosymmetric space groups. Two polymorphs have Z′ > 1. The structures are assembled via interactions between carbonyl groups of quinoid fragments into layers which further interact only by weak interactions.

The structure of two manganese hexacyanometallates(II): Mn2[Fe(CN)6].8H2O and Mn2[Os(CN)6].8H2O

2002 ◽  
Vol 17 (2) ◽  
pp. 144-148 ◽  
Author(s):  
A. Gómez ◽  
V. H. Lara ◽  
P. Bosch ◽  
E. Reguera
Keyword(s):  
Crystal Structures ◽  
Coordination Sphere ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structural Model ◽  
Rietveld Method ◽  
Monoclinic Space Group ◽  
Powder Diffraction Data ◽  
Crystallization Water ◽  
X Ray

The crystal structures of two manganese hexacyanometallates(II), Mn2[Fe(CN)6].8H2O and Mn2[Os(CN)6].8H2O, were refined from X-ray powder diffraction data using the Rietveld method, with the reported structure for Mn2[Ru(CN)6].8H2O used as a structural model. These compounds are isomorphous and crystallize in the monoclinic space group P21/n. Their crystallization water is not firmly bound and can be removed without disrupting the M–C≡N–Mn network. In the dehydrated complexes, the outer cation (Mn) remains linked to only three N atoms from CN ligands while the inner cation (Fe,Os) preserves its coordination sphere. The IR, Raman, and Mössbauer spectra for the hydrated and anhydrous forms are explained based on the refined structures.

Crystal Structure of the New Compound TbCo0.67Ga1.33

2015 ◽  
Vol 1089 ◽  
pp. 102-106
Author(s):  
Liu Qing Liang ◽  
Wen Jun Shen ◽  
Ling Min Zeng ◽  
Cai Min Huang
Keyword(s):  
Crystal Structure ◽  
Rietveld Refinement ◽  
Ternary Compound ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Structure Type ◽  
Powder Diffraction Data ◽  
Space Group ◽  
X Ray

A new ternary compound TbCo0.67Ga1.33 was discovered and studied by means of X-ray powder diffraction technique. The crystal structure of the new compound was refined by using Rietveld method from X-ray powder diffraction data. This compound crystallizes in the orthorhombic with the CeCu2 structure type( space group Imma, a = 0.43384(6) nm, b = 0.70193(1) nm, c = 0.75617(1) nm, Z = 4, and Dcalc = 8.512 g/cm3 ). The Rietveld refinement results were Rp = 0.0996, Rwp = 0.1277.

The crystal structures of solvent-free alkali-metal squarates from powder diffraction data

2005 ◽  
Vol 220 (11) ◽  
Author(s):  
Robert E. Dinnebier ◽  
Hanne Nuss ◽  
Martin Jansen
Keyword(s):  
High Resolution ◽  
Alkali Metal ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Room Temperature ◽  
Solvent Free ◽  
Crystallographic Data ◽  
Powder Diffraction Data ◽  
X Ray

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

Rietveld Refinement of the BaTiO3 from X-Ray Powder Diffraction

2009 ◽  
Vol 79-82 ◽  
pp. 593-596
Author(s):  
Feng Sun ◽  
Yan Sheng Yin
Keyword(s):  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Structural Parameters ◽  
Ferroelectric Ceramic ◽  
Powder Diffraction Data ◽  
Ceramic Powders ◽  
Space Group ◽  
X Ray

The ferroelectric ceramic BaTiO3 was synthesized at 1000 °C for 5 h. The structure of the system under study was refined on the basis of X-ray powder diffraction data using the Rietveld method. The system crystallizes in the space group P4mm（99）. The refinement of instrumental and structural parameters led to reliable values for the Rp, Rwp and Rexp.We use the TOPAS software of Bruker AXS to refine this ceramic powders and show its conformation

The BaAl4 Structure and its Derivatives from the R-Zn-Ga Systems

2012 ◽  
Vol 194 ◽  
pp. 5-9 ◽  
Author(s):  
Yuriy Verbovytskyy ◽  
Antonio Pereira Gonçalves
Keyword(s):  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Powder Diffraction Data ◽  
Space Group ◽  
X Ray ◽  
First Time

Seven new ternary RZn1+xGa3-x (R = Ce, Pr, Nd, Sm, Ho and Er) and R5Zn2Ga17 (R = Ce) phases are synthesized for the first time. Their crystal structures are solved on basis of X-ray powder diffraction data. The above mentioned compounds belong to the BaAl4 (space group I4/mmm) and Rb5Hg19 (space group I4/m) structure types. Details of the structure of the Ce5Zn2Ga17 compound and relationship with RZn2-xGa2+x (BaAl4 type) and R3Zn8-xGa3+x (La3Al11 type) are briefly discussed.

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