Advances in space-group determination from powder diffraction data

2007 ◽  
Vol 40 (4) ◽  
pp. 743-748 ◽  
Author(s):  
Angela Altomare ◽  
Mercedes Camalli ◽  
Corrado Cuocci ◽  
Carmelo Giacovazzo ◽  
Anna Grazia Giuseppina Moliterni ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Large Set ◽  
Powder Diffraction Data ◽  
New Approach ◽  
Extinction Group ◽  
Space Group ◽  
Determination Process ◽  
New Algorithms

The space-group determination process by powder diffraction data is not straightforward. The low accuracy of the reflection intensities may invalidate the calculation of the probability associated to each extinction group that is compatible with the crystal system determined in the indexation step. Here the combination of thezstatistics with two new algorithms is reported: the first checks the quality of each 2θ interval in order to omit doubtfulzestimates from the calculations; the second creates a list of reflections with peaks that weakly overlap with any other peak, in order to check if any of them violates the extinction rules of the extinction symbol. The new approach has been applied to a large set of test structures and proved to be much more efficient than the procedure based only on thezstatistics.

The Shift_and_Fix procedure inEXPO: advances for solvingab initiocrystal structures by powder diffraction data

2017 ◽  
Vol 50 (6) ◽  
pp. 1812-1820 ◽  
Author(s):  
Angela Altomare ◽  
Corrado Cuocci ◽  
Anna Moliterni ◽  
Rosanna Rizzi ◽  
Nicola Corriero ◽  
...  
Keyword(s):  
Ab Initio ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Solution Process ◽  
Direct Methods ◽  
Structure Model ◽  
Powder Diffraction Data ◽  
New Approach ◽  
Chemical Content

The Shift_and_Fix procedure is a new method which has been developed for improving the quality of a structure model obtained by theab initiosolution process from powder diffraction data. The main features of the new approach, which is fully automatic, are as follows: (a) the structure model usually attained at the end of the phasing process by direct methods is shifted partly and randomly; (b) a combination of Fourier map calculation and least-squares cycles has been designed for relocating the shifted atoms onto positions which can finally be moved onto the true ones by the standard model optimization approaches; (c) the Fourier map is calculated using coefficients which depend on the chemical content of the compound under study. When the figure of merit for selecting the best set of phases derived by direct methods does not work well, the ALLTRIALS strategy can be applied: it aims to investigate, automatically and sequentially, all the stored direct methods phasing sets and pick up the correct solution. The Shift_and_Fix method has been applied for improving the structure model calculated by each one of the phasing sets processed by ALLTRIALS. It has been implemented in the computer programEXPOand proved to be effective in providing a better ALLTRIALS outcome and increasing the probability of succeeding in theab initiopowder solution.

X-ray powder diffraction data for Ba3MnSi2O8—A new phase in the system BaO–MnO–SiO2

1996 ◽  
Vol 11 (1) ◽  
pp. 26-27 ◽  
Author(s):  
Irena Georgieva ◽  
Ivan Ivanov ◽  
Ognyan Petrov
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Data Interpretation ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Phase

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.

X-ray powder diffraction data for tetrazene nitrate monohydrate, C2H9N11O4

2021 ◽  
pp. 1-3
Author(s):  
J. Maixner ◽  
J. Ryšavý
Keyword(s):  
Cell Volume ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

X-ray powder diffraction data, unit-cell parameters, and space group for tetrazene nitrate monohydrate, C2H9N11O4, are reported [a = 5.205(1) Å, b = 13.932(3) Å, c = 14.196(4) Å, β = 97.826(3)°, unit-cell volume V = 1019.8(4) Å3, Z = 4, and space group P21/c]. All measured lines were indexed and are consistent with the P21/c space group. No detectable impurities were observed.

Powder X-ray diffraction of 3,3-dichloro-1-(4-nitrophenyl)-2-piperidinone, C11H10Cl2N2O3

2015 ◽  
Vol 30 (3) ◽  
pp. 293-293 ◽  
Author(s):  
Qing Wang ◽  
Ying Xiao ◽  
Jia Wei He ◽  
Hui Li
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

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.

Crystal data and X-ray powder diffraction data of 2,4-diiodo-4-nitrophenol (disophenol), C6H3I2NO3. More precise X-ray powder diffraction data of p-nitrophenol, C6H5NO3

1996 ◽  
Vol 11 (4) ◽  
pp. 301-304
Author(s):  
Héctor Novoa de Armas ◽  
Rolando González Hernández ◽  
José Antonio Henao Martínez ◽  
Ramón Poméz Hernández
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell ◽  
Crystal Data ◽  
Powder Diffraction Data ◽  
Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Monoclinic Cell

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.

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

X-ray powder diffraction data for ertapenem side chain, C20H19N3O7S

2017 ◽  
Vol 32 (3) ◽  
pp. 203-205
Author(s):  
Xiang Lin ◽  
Wei Ling Zhuo ◽  
Qiao Hong Du ◽  
Xi Lin Peng ◽  
Hui Li
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Side Chain ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

X-ray powder diffraction data, unit-cell parameters, and space group for ertapenem side chain, C20H19N3O7S, are reported [a = 4.907(6) Å, b = 18.686(3) Å, c = 22.071(1) Å, α = γ = 90°, β = 90.759(5)°, unit-cell volume V = 2023.82 Å3, Z = 4, ρcal = 1.462 g cm−3, and space group P21/c]. All measured lines were indexed and are consistent with the P21/c space group. No detectable impurity was observed.

X-ray powder diffraction data for copper(II), bis[(2E)-3-methoxy-2-[(2,6-dimethylphenyl)imino]-4-[(2,6-dimethylphenyl)imino-κN]-3-pentanolato-κO] complex

2013 ◽  
Vol 28 (4) ◽  
pp. 296-298
Author(s):  
R. Pažout ◽  
J. Maixner ◽  
A.S. Jones ◽  
J. Merna
Keyword(s):  
Cell Volume ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

X-ray powder diffraction data, unit-cell parameters, and space group for a new bis(β-diiminato) Cu(II) complex, C44H54CuN4O4, are reported [a = 8.683(3) Å, b = 11.216(3) Å, c = 11.753(4) Å, α = 66.27(3), β = 84.61(3), γ = 78.85(3), unit-cell volume V = 1027.77 Å3, Z = 1, and space group P-1]. All measured lines were indexed and are consistent with the P-1 space group. No detectable impurity was observed.

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.

X-ray powder diffraction data for deoxyschisandrin

2013 ◽  
Vol 28 (3) ◽  
pp. 231-233 ◽  
Author(s):  
Li Li Zhang ◽  
Qing Qing Pan ◽  
Dan Xiao ◽  
Xiao Qing Wu ◽  
Qing Wang ◽  
...  
Keyword(s):  
Cell Volume ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

X-ray powder diffraction data, unit-cell parameters, and space group for deoxyschisandrin, C24H32O6, are reported [a = 13.083(3) Å, b = 19.563(9) Å, c = 8.805(6) Å, β = 90.472(0)°, unit-cell volume V = 2253.82 Å3, Z = 4, and space group P21]. All measured lines were indexed and are consistent with the P21 space group. No detectable impurity was observed.

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