Improved powder diffraction patterns for synthetic paranatisite and natisite

2002 ◽  
Vol 17 (3) ◽  
pp. 234-237 ◽  
Author(s):  
S. Ferdov ◽  
V. Kostov-Kytin ◽  
O. Petrov

Synthetic analogues of the minerals natisite and for the first time of paranatisite were prepared hydrothermally at 200 °C in the system Na2O–TiO2–SiO2–H2O. The obtained powder x-ray diffraction (XRD) patterns were interpreted by the Powder Data Interpretation (PDI) software package. As a result improved indexing and unit cell parameters refinements of these two phases were achieved. Synthetic natisite is tetragonal, space group—P4/nmm, a=0.649 67(8) nm, c=0.508 45(11) nm, V=0.214 50(10) nm3, Z=2, Dcal=3.13 g.cm−1, F30=37.48, M20=52.79. Synthetic paranatisite is orthorhombic, space group—Pmma, a=0.983 86(29) nm, b=0.919 23(19) nm, c=0.481 84(12) nm, V=0.435 78(19) nm3, Z=1, Dcal=3.01 g.cm−1, F30=16.42, M20=29.21.

1996 ◽  
Vol 11 (1) ◽  
pp. 9-12
Author(s):  
W. Wong-Ng

Calculated patterns for the BaR2PdO5 series, in which X is Pd and R=Nd, Sm, Eu, or Gd, have been prepared for materials characterization until experimental patterns can be determined. These compounds are isostructural to the superconductor related “brown phases” BaLa2CuO5 and BaNd2CuO5, which are tetragonal with space group P4/mbm, Z=4. The cell parameters of the Eu and Gd compounds were derived from the La and Nd analogs. The calculated patterns of these four compounds compared well to an experimental pattern of BaNd2CuO5.


2007 ◽  
Vol 62 (10) ◽  
pp. 1271-1276 ◽  
Author(s):  
Liang Chen ◽  
Xian-Wen Wanga ◽  
Jing-Zhong Chen ◽  
Jian-Hong Liu

The complexes Mn(Cl3CCOO)2(4,4′-bpy) (1) and [Cu2(ClCH2COO)(2,2′-bpy)2(OH)(H2O)]-(NO3)2(2) (bpy = bipyridine) were generated under mild reaction conditions and characterized by IR spectra, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), and single crystal X-ray diffraction. Compound 1 exhibits a two-dimensional network with octahedrally coordinated Mn(II) atoms linked by 4,4′-bpy ligands and Cl3COO− ligands. Compound 2 features a supramolecular structure of binuclear complexes, with edge-sharing five-coordinated square-pyramidal units bridged by the ClCH2COO− ligand, an OH− group and a water molecule. Complex 1 crystallizes in the orthorhombic space group Pbcn with cell parameters: a = 16.5390(17), b = 11.6396(17), c = 9.9181(12) Å, V = 1909.3(4) Å3, Z = 4, wR2 = 0.1576. Complex 2 crystallizes in the triclinic space group P1̅ with cell parameters: a = 7.6190(15), b = 11.151(2), c = 16.640(3) Å , α = 73.13(3), β = 80.89(3), γ = 74.51(3)°, V = 1298.73(4) Å3, Z = 2, wR2 = 0.1265.


2010 ◽  
Vol 25 (4) ◽  
pp. 349-354 ◽  
Author(s):  
Y. Q. Chen ◽  
J. K. Liang ◽  
J. Luo ◽  
J. B. Li ◽  
G. H. Rao

The structure transitions and phase relationships of DyFe3−xAlx compounds have been investigated by X-ray powder diffraction. Our XRD results show that each of the compounds with x≤0.45 crystallizes in the rhombohedral PuNi3-type structure with space group R3¯m and Z=9; for the 0.8≤x<1.0 compounds, each has a hexagonal structure of the CeNi3 type with space group P63/mmc and Z=6; and each of the samples with 0.45<x<0.8 is a two-phase mixture of the PuNi3- and CeNi3-type structures. The calculated XRD intensities of the DyFe3−xAlx compounds with x=0.2, 0.33, 0.4, and 0.45 indicate that Dy occupies the 3a and 6c sites, Fe and Al distribute randomly on the 18h site, and the 3b and 6c sites are exclusively occupied by Fe, which agrees well with those of our experimental XRD patterns. The XRD intensities of the DyFe3−xAlx compounds with x=0.8 and 1.0 have also been calculated and found to agree with the experimental results with Dy on the 2c and 4f sites, Fe and Al at the 12k site, and Fe at the 2a, 2b, and 2d sites. In the two-phase region with x=0.45–0.8, the values of unit-cell parameters and phase compositions are linearly dependent on the value of x, indicating that the two phases are constituted by the same composition x with different stacking arrangements. This abnormal two-phase equilibrium is further confirmed by the structural analysis of the DyFe2.33Al0.67 (or x=0.67) sample. The samples with x=1.1 and 1.2 were also analyzed, and each found to be a mixture of more than two phases.


2016 ◽  
Vol 31 (2) ◽  
pp. 155-158
Author(s):  
Shoujun Zheng ◽  
Kailin Xu ◽  
Qing Wang ◽  
XiaoLin Tang ◽  
Yanmei Huang ◽  
...  

2-[((3R)-5-oxo-4-phenyltetrahydrofuran-3-yl)methyl]isoindoline-1,3-dione, C19H15NO4, was synthesized for the first time. Its structure was characterized by element analysis, ultraviolet spectrometry, nuclear magnetic resonance, and single X-ray diffraction (SXRD). X-ray powder diffraction (XRPD) data of title compound were collected and calculated. The result of SXRD shows that its crystal system is orthorhombic, space group is Pbca, and unit-cell parameters are a = 8.861 57(7), b = 14.6666(10), c = 24.4247(19) Å, α =β =γ =90°, unit-cell volume V = 3174.4 Å3, and Z = 8. All XRPD measured lines were indexed and consistent with the Pbca space group [a = 14.639(7), b = 24.378(3), c = 8.918(1) Å, α = β = γ = 90°, unit-cell volume V = 3182.7(9) Å3, Z = 8]. No detectable impurities were observed.


1981 ◽  
Vol 36 (2) ◽  
pp. 161-171 ◽  
Author(s):  
Joachim Fuchs ◽  
Axel Thiele ◽  
Rosemarie Palm

Abstract Dodecatungstosilicates free of crystal water were prepared for the first time by using tetraalkylammonium as cation. The crystal structure of the tetramethylammonium a-dodeeatungstosilicate [N(CH3)4]4SiW12O40 (1) and tetrabutylammonium) β-dodecatungstosilicate, [N(C4H9)4]4SiWi2040 (2) were solved by X-ray diffraction. (1) crystallizes tetragonal in the space group 14̅ with lattice parameters a = 14.642 Å; c= 12.706 Å; (2) orthorhombic, space group P212121 with a = 29.277 Å, b = 22.181 Å and c = 15.381 Å. The differences between the two isomeric heteropolyanions are discussed, especially the distances and angles between the tungsten atoms. Comparison of characteristic differences in the vibrational spectra permits the identification of the isomeric anions.


1982 ◽  
Vol 26 ◽  
pp. 63-72 ◽  
Author(s):  
Nikos P. Pyrros ◽  
Camden R. Hubbard

The production of standard x-ray diffraction patterns at NBS imposes special requirements in the data processing of powder patterns. The patterns should be complete and have an overall accuracy of better than 0.01 degree two theta. To ensure completeness all the observable peaks should be indexed. To make certain that the sample is a pure phase, weak peaks have to be identified as well.The indexing of all the peaks implies that the cell constants must be known and there should be a good agreement between all the calculated and observed peak positions. In practice this is achieved by a least-squares refinement of the unit cell parameters. This serves as a test of the assumed unit cell and also as an interpretation of the observed peaks. Finally, an attempt is made to identify the space group. This step also requires the identification of weak peaks. The agreement of a known space group with the observed reflections further confirms the purity of the sample.


2004 ◽  
Vol 19 (4) ◽  
pp. 378-384
Author(s):  
A. Rafalska-Lasocha ◽  
M. Grzywa ◽  
B. Włodarczyk-Gajda ◽  
W. Lasocha

The X-ray diffraction patterns of two organic acids 1-naphthalenesulfonic acid dihydrate and 2-naphthalenesulfonic acid hydrate were measured at room temperature. Complexes of these acids with 1,8-bis(dimethylamino)naphthalene (DMAN) were synthesized, purified and investigated by means of X-ray powder diffraction. 1-Naphthalenesulfonic acid dihydrate as well as its complex with 1,8-bis(dimethylamino)naphthalene crystallize in the monoclinic system with unit cell parameters refined to a=0.91531(8) nm, b=0.7919(1) nm, c=0.8184(1) nm, β=101.618(9)° space group P21/m (11) and a=1.7781(4) nm, b=2.0122(4) nm, c=1.2337(2) nm, β=96.54(3)°, space group C2/m (12), respectively. 2-Naphthalenesulfonic acid hydrate crystallizes in the orthorhombic system with a=2.2749(3) nm, b=0.7745(1) nm, c=0.591 36(9) nm, space group Pnma, whereas its complex with 1,8-bis(dimethylamino)naphthalene crystallizes in the triclinic system a=1.3969(6) nm, b=1.4292(5) nm, c=1.1741(6) nm, α=90.93(3)°, β=98.14(3)°, γ=113.93(3)°, space group P-1 (2).


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuta Suzuki ◽  
Hideitsu Hino ◽  
Takafumi Hawai ◽  
Kotaro Saito ◽  
Masato Kotsugi ◽  
...  

AbstractDetermination of crystal system and space group in the initial stages of crystal structure analysis forms a bottleneck in material science workflow that often requires manual tuning. Herein we propose a machine-learning (ML)-based approach for crystal system and space group classification based on powder X-ray diffraction (XRD) patterns as a proof of concept using simulated patterns. Our tree-ensemble-based ML model works with nearly or over 90% accuracy for crystal system classification, except for triclinic cases, and with 88% accuracy for space group classification with five candidates. We also succeeded in quantifying empirical knowledge vaguely shared among experts, showing the possibility for data-driven discovery of unrecognised characteristics embedded in experimental data by using an interpretable ML approach.


2011 ◽  
Vol 26 (4) ◽  
pp. 346-349 ◽  
Author(s):  
M. A. Macías ◽  
J. A. Henao ◽  
Lina María Acosta ◽  
Alirio Palma

The 6,8-dimethyl-cis-2-vinyl-2,3,4,5-tetrahydro-1H-benzo[b]azepin-4-ol (2a) (Chemical formula C14H19NO) and 8-chloro-9-methyl-cis-2-(prop-1-en-2-yl)-2,3,4,5-tetrahydro-1H-benzo[b]azepin-4-ol (2b) (Chemical formula C14H18ClNO) were prepared via the reductive cleavage of the bridged N-O bond of the corresponding 1,4-epoxytetrahydro-1-benzazepines. The X-ray powder diffraction patterns for the new compounds were obtained. The compound 2a was found to crystallize in an orthorhombic system with space group Pmn21 (No. 31), refined unit-cell parameters a = 19.422(6) Å, b = 6.512(3) Å, c = 9.757(4) Å and V = 1234.0(5) Å3. The compound 2b was found to crystallize in a monoclinic system with space group P21/m (No. 11), refined unit-cell parameters a = 17.570(4) Å, b = 8.952(3) Å, c = 14.985(4) Å, β = 101.66(2)°, and V = 2308.3(9) Å3.


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.


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