FOX: Modular Approach to Crystal Structure Determination from Powder Diffraction

2004 ◽  
Vol 443-444 ◽  
pp. 35-38 ◽  
Author(s):  
V. Favre-Nicolin ◽  
R. Černý
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Structure Determination ◽  
Building Blocks ◽  
Adaptive Method ◽  
Crystal Structure Determination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neighboring Building ◽  
Diffraction Patterns

Program FOX for ab initio crystal structure determination from powder diffraction uses global optimization algorithms to find the correct structure by making trials in the direct space. It is a modular program, capable of using several criteria for evaluating each trial configuration, e.g. combining neutron and X-ray diffraction patterns. The program describes the structural building blocks (polyhedrons, molecules etc.) with their internal coordinates (Z-matrices), thus allowing natural constraints on interatomic distances and angles. Identical atoms shared between neighboring building blocks, and special positions are handled with an automatic, adaptive method (Dynamical Occupancy Correction). Several algorithms (Simulated Annealing, Parallel Tempering) are currently available. The program is based on an object-oriented crystallographic library ObjCryst++(programming language c++). The program and the library are available for Linux and Windows on http://objcryst.sourceforge.net. Inorganic and organic structures with the complexity up to 26 independents atoms are routinely solved from laboratory X-ray, synchrotron or neutron data.

The X-Ray Powder Diffraction Patterns and Crystal Structure for Al2M3Y(M=Cu, Ni)

2014 ◽  
Vol 950 ◽  
pp. 48-52
Author(s):  
De Gui Li ◽  
Ming Qin ◽  
Liu Qing Liang ◽  
Zhao Lu ◽  
Shu Hui Liu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Hexagonal Structure ◽  
Argon Atmosphere ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Arc Melting ◽  
Diffraction Patterns

The Al2M3Y(M=Cu, Ni) compound was synthesized by arc melting under argon atmosphere. The high-quality powder X-ray diffraction data of Al2M3Y have been presented. The refinement of the X-ray diffraction patterns for the Al2M3Y compound show that the Al2M3Y has hexagonal structure, space groupP6/mmm(No.191), with a = b = 5.1618(2) Å, c = 4.1434(1) Å,V= 95.6 Å3,Z= 1,ڑx= 5.7922 g/cm3,F30= 155.5(0.0057, 34), RIR = 2.31 for Al2Cu3Y, and with a = b = 5.0399(1) Å, c = 4.0726(1) Å,V= 89.59 Å3,Z= 1,ڑx= 5.9118 g/cm3,F30= 135.7(0.0072, 30), RIR = 2.54 for Al2Ni3Y.

A synergic approach of X-ray powder diffraction and Raman spectroscopy for crystal structure determination of 2,3-thienoimide capped oligothiophenes

2018 ◽  
Vol 20 (5) ◽  
pp. 3630-3636 ◽  
Author(s):  
C. Cappuccino ◽  
P. P. Mazzeo ◽  
T. Salzillo ◽  
E. Venuti ◽  
A. Giunchi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Raman Spectroscopy ◽  
Powder Diffraction ◽  
Structure Determination ◽  
Molecular Conformation ◽  
Rapid Identification ◽  
Crystal Structure Determination ◽  
X Ray

This work presents a Raman based approach for the rapid identification of the molecular conformation in a series of new 2,3-thienoimide capped quaterthiophenes.

Crystal structure determination of Ag2Ga by single crystal X-ray diffraction

1998 ◽  
Vol 213 (12) ◽  
Author(s):  
A. E. Gunnæs ◽  
A. Olsen ◽  
P. T. Zagierski ◽  
B. Klewe ◽  
O. B. Karlsen ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Structure Determination ◽  
Crystal Structure Determination ◽  
X Ray Diffraction ◽  
X Ray

AbstractThe crystal structure of

A synchrotron X-ray powder diffraction study of 4-(2,3,4-trifluorophenyl)-1,2,3,5-dithiadiazolyl. Crystal structure determination using a global optimisation method

1999 ◽  
Vol 23 (6) ◽  
pp. 565-567 ◽  
Author(s):  
Anthony M. T. Bell ◽  
J Nicholas B. Smith ◽  
J Paul Attfield ◽  
Jeremy M. Rawson ◽  
Kenneth Shankland ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Diffraction Study ◽  
Powder Diffraction ◽  
Structure Determination ◽  
Global Optimisation ◽  
Crystal Structure Determination ◽  
X Ray

scholarly journals Some reflections on symmetry: pitfalls of automation and some illustrative examples

2019 ◽  
Vol 75 (12) ◽  
pp. 1812-1819 ◽  
Author(s):  
William Clegg
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Crystal Structure Determination ◽  
Structure Validation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Determinations ◽  
Basic Concepts ◽  
Software Automation

In the context of increasing hardware and software automation in the process of crystal structure determination by X-ray diffraction, and based on conference sessions presenting some of the experience of senior crystallographers for the benefit of younger colleagues, an outline is given here of some basic concepts and applications of symmetry in crystallography. Three specific examples of structure determinations are discussed, for which an understanding of these aspects of symmetry avoids mistakes that can readily be made by reliance on automatic procedures. Topics addressed include pseudo-symmetry, twinning, real and apparent disorder, chirality, and structure validation.

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