Powder X-ray diffraction of Metastudtite, (UO2)O2(H2O)2

2016 ◽  
Vol 31 (1) ◽  
pp. 71-72 ◽  
Author(s):  
Mark A. Rodriguez ◽  
Philippe E. Weck ◽  
Joshua D. Sugar ◽  
Thomas J. Kulp

There has been some confusion in the published literature concerning the structure of Metastudtite (UO2)O2(H2O)2 where differing unit cells and space groups have been cited for this compound. Owing to the absence of a refined structure for Metastudtite, Weck et al. (2012) have documented a first-principles study of Metastudtite using density functional theory (DFT). Their model presents the structure of Metastudtite as an orthorhombic (space group Pnma) structure with lattice parameters of a = 8.45, b = 8.72, and c = 6.75 Å. A Powder Diffraction File (PDF) database entry has been allocated for this hypothetical Metastudtite phase based on the DFT modeling (see 01-081-9033) and aforementioned Dalton Trans. manuscript. We have obtained phase pure powder X-ray diffraction data for Metastudtite and have confirmed the model of Weck et al. via Rietveld refinement (see Figure 1). Structural refinement of this powder diffraction dataset has yielded updated refined parameters. The new cell has been determined as a = 8.411(1), b = 8.744(1), and c = 6.505(1) Å; cell volume = 478.39 Å3. There are only subtle differences between the refined structure and that of the first-principles model derived from DFT. Notably, the b-axis is significantly contracted in the final refinement as compared with DFT. There were also subtle changes to the U1, O1, and O3 atom positions. Tabulated powder diffraction data (d's and I's) for the Metastudtite have been derived from the refined model and these new values can serve to augment the PDF entry 01-081-9033 with a more updated entry based on observed X-ray powder diffraction data.

Author(s):  
Dongmin Lee ◽  
Hyeri Bu ◽  
Dohwan Kim ◽  
Jooeun Hyoung ◽  
Seung-Tae Hong

The crystal structure of calcium perchlorate anhydrate was determined from laboratory X-ray powder diffraction data. The title compound was obtained by heating hydrated calcium perchlorate [Ca(ClO4)2·xH2O] at 623 K in air for 12 h. It crystallizes in the orthorhombic space group Pbca and is isotypic with Ca(AlD4)2. The asymmetric unit contains one Ca, two Cl and eight O sites, all on general sites (Wyckoff position 8c). The crystal structure consists of isolated ClO4 − tetrahedra and Ca2+ cations. The Ca2+ cation is coordinated by eight O atoms of eight symmetry-related ClO4 − tetrahedra within a distorted square-antiprismatic environment.


2014 ◽  
Vol 70 (a1) ◽  
pp. C1442-C1442
Author(s):  
Karthikeyan Natarajan ◽  
Sathya Duraisamy ◽  
Sivakumar Kandasamy

X -ray diffraction becomes a routine process these decades for determining crystal structure of the materials. Most of the crystal structures solved nowadays is based on single crystal X-ray diffraction because it solves the crystal and molecular structures from small molecules to macro molecules without much human intervention. However it is difficult to grow single crystals of sufficient size and quality for conventional single-crystal X-ray diffraction studies. In such cases it becomes essential that structural information can be determined from powder diffraction data. With the recent developments in the direct-space approaches for structure solution, ab initio crystal structure analysis of molecular solids can be accomplished from X-ray powder diffraction data. It should be recalled that crystal structure determination from laboratory X-ray powder diffraction data is a far more difficult task than that of its single-crystal counterpart, particularly when the molecule possesses considerable flexibility or there are multiple molecules in the asymmetric unit. Salicylic acid and its derivatives used as an anti-inflammatory drug are known for its numerous medicinal applications. In our study, we synthesized mononuclear copper (II) complex of salicylate derivative. The structural characterization of the prepared compound was carried out using powder X-ray diffraction studies. Crystal structure of the compound has been solved by direct-space approach and refined by a combination of Rietveld method using TOPAS Academic V4.1. Density Functional Theory (DFT) calculations have to be carried in the solid state for the compound using GaussianW9.0 in the frame work of a generalized-gradient approximation (GGA). The geometry optimization was to be performed using B3LYP density functional theory. The atomic coordinates were taken from the final X-ray refinement cycle.


2021 ◽  
pp. 1-3
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton

The crystal structure of varenicline hydrogen tartrate Form B (Chantix®) has been refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Varenicline hydrogen tartrate Form B crystallizes in space group P212121 (#19) with a = 7.07616(2), b = 7.78357(2), c = 29.86149(7) Å, V = 1644.706(6) Å3, and Z = 4. The hydrogen bonds were identified and quantified. Hydrogen bonds link the cations and anions in zig-zag chains along the b-axis. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).


1986 ◽  
Vol 1 (2) ◽  
pp. 33-34 ◽  
Author(s):  
D. F. Mullica ◽  
E. L. Sappenfield

AbstractThe indexed X-ray diffraction powder data of trans-bis(dimethylphenylphosphine)bis(pyrazole)platinum, {Pt(C3H4N2)2[P(CH3)2(C6H5)]2, PTPP} and trans-(tricyclohexylphosphino) (triethylphosphino) platinum(II) chloride, (PtCl2P2C24H48, PTHE) are reported. PTPP crystallizes in the monoclinic space group C2/c and PTHE crystallizes in the orthorhombic space group Pcab. The refined cell parameters were determined by employing a Siemens Debye-Scherrer camera (Fe radiation, λmean = 1.93736 Å). The cell constants are a = 21.516(5), b = 6.287(1), c = 17.929(4)Å, β = 102.51(1)°, V = 2367.7Å3 Dx=1.70Mg m−3, Dm = 1.70Mg m−3 for PTPP and a = 12.271(1), b = 19.375(1), c = 23.864(3)Å, V = 5673.4Å3, Dx = 1.553Mg m−3 for PTHE. The quantitative figures of merit (FN) are F23 = 47(0.010,51) [F20 = 60(0.009,35)] for PTPP and F30 = 12(0.008,324) [F20 = 27(0.017,105)] for PTHE. The JCPD S Diffraction File No. for PTPP is 37-1999 and for PTHE is 37-2000.


1996 ◽  
Vol 11 (1) ◽  
pp. 26-27 ◽  
Author(s):  
Irena Georgieva ◽  
Ivan Ivanov ◽  
Ognyan Petrov

A new compound—Ba3MnSi2O8 in the system BaO–MnO–SiO2 was synthesized and studied by powder X-ray diffraction. The compound is hexagonal, space group—P6/mmm, a=5.67077 Å, c=7.30529 Å, Z=1, Dx=5.353. The obtained powder X-ray diffractometry (XRD) data were interpreted by the Powder Data Interpretation Package.


2015 ◽  
Vol 30 (3) ◽  
pp. 293-293 ◽  
Author(s):  
Qing Wang ◽  
Ying Xiao ◽  
Jia Wei He ◽  
Hui Li

X-ray powder diffraction data for 3,3-dichloro-1-(4-nitrophenyl)-2-piperidinone, C11H10Cl2N2O3, are reported [a = 11.088(4) Å, b = 11.594(5) Å, c = 12.689(3) Å, α = 118.456(1)°, β = 100.320(3)°, γ = 107.763(3)°, V = 1259.27 Å3, Z = 4 and space group P-1 ]. All measured lines were indexed and are consistent with the P-1 space group. No detectable impurities were observed.


2016 ◽  
Vol 31 (4) ◽  
pp. 292-294 ◽  
Author(s):  
V. D. Zhuravlev ◽  
A. P. Tyutyunnik ◽  
N. I. Lobachevskaya

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.


1997 ◽  
Vol 53 (6) ◽  
pp. 861-869 ◽  
Author(s):  
C. D. Ling ◽  
J. G. Thompson ◽  
S. Schmid ◽  
D. J. Cookson ◽  
R. L. Withers

The structures of the layered intergrowth phases SbIIISb^{\rm V}_xAl-xTiO6 (x \simeq 0, A = Ta, Nb) have been refined by the Rietveld method, using X-ray diffraction data obtained using a synchrotron source. The starting models for these structures were derived from those of Sb^{\rm III}_3Sb^{\rm V}_xA 3−xTiO14 (x = 1.26, A = Ta and x = 0.89, A = Nb), previously solved by single-crystal X-ray diffraction. There were no significant differences between the derived models and the final structures, validating the approach used to obtain the models and confirming that the n = 1 and n = 3 members of the family, Sb^{\rm III}_nSb^{\rm V}_xA n−xTiO4n+2 are part of a structurally homologous series.


2008 ◽  
Vol 23 (4) ◽  
pp. 356-359 ◽  
Author(s):  
B. Grushko ◽  
D. Pavlyuchkov

Ternary Al–Cu–Ir phases, isostructural to the Al–Cu–Rh ω and C2 phases, were found to be around the Al70Cu20Ir10 and Al60Cu15Ir25 compositions, respectively. Using powder X-ray diffraction, the former was found to have a tetragonal structure (space group P4/mnc) with a=6.4142(9) Å and c=14.842(4) Å, and the latter has a cubic structure (space group Fm3) with a=15.3928(6) Å.


2010 ◽  
Vol 163 ◽  
pp. 173-176
Author(s):  
Lucjan Pająk ◽  
E. Olszewska ◽  
Stanislaw Pikus ◽  
Grzegorz Dercz ◽  
Józef Rasek

In the present work X-ray studies were performed on annealed Fe78Nb2B20 amorphous alloy prepared by melt-spinning technique. All the samples were annealed in vacuum for 1 hour at temperatures up to 800°C. For the studied alloy -Fe and Fe2B are the stable, crystalline phases. The -Fe crystallized as the first crystalline phase in the sample annealed at 350°C. On the other hand, metastable Fe3B phase appeared to be stable during annealing in 425-800°C temperature range. The best fitting of the experimental X-ray data to as jet available ICDD files was obtained for Ni3P type structure (39-1315 – S.G.: I (82)). New, experimental powder diffraction data for metastable Fe3B phase prepared according to ICDD standards were elaborated for the sample annealed at 600°C. For this sample the best agreement between the calculated values of lattice constants and positions of experimental diffraction lines was obtained. The X-ray data were collected using X-Pert Philips diffractometer equipped with curved graphite monochromator on diffracted beam. The Treor program was applied for the analysis of X-ray diffraction data.


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