scholarly journals Improved crystal structure solution from powder diffraction data by the use of conformational information

2017 ◽  
Vol 50 (5) ◽  
pp. 1421-1427 ◽  
Author(s):  
Elena A. Kabova ◽  
Jason C. Cole ◽  
Oliver Korb ◽  
Adrian C. Williams ◽  
Kenneth Shankland
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Structure Determination ◽  
Powder Diffraction Data ◽  
Structure Solution ◽  
Structural Database ◽  
Complex Crystal

The effect of introducing conformational information to theDASHimplementation of crystal structure determination from powder diffraction data is investigated using 51 crystal structures, with the aim of allowing increasingly complex crystal structures to be solved more easily. The findings confirm that conformational information derived from the Cambridge Structural Database is indeed of value, considerably increasing the chances of obtaining a successful structure determination. Its routine use is therefore encouraged.

Crystal structure determination from powder diffraction data by the application of a genetic algorithm

1997 ◽  
Vol 212 (8) ◽  
Author(s):  
K. Shankland ◽  
W. I. F. David ◽  
T. Csoka
Keyword(s):  
Crystal Structure ◽  
Genetic Algorithm ◽  
Full Advantage ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Structure Determination ◽  
Powder Diffraction Data ◽  
Flexible Molecules

AbstractA genetic algorithm (GA) based method for solving crystal structures directly from powder diffraction data has been developed. The method is based around fitting the diffraction data generated from trial structures against the measured diffraction data and has the ability to handle flexible molecules and multiple fragments. It is computationally highly efficient and takes full advantage of the implicit parallelism of the GA. The method is illustrated with the solutions of three crystal structures of varying complexity.

RECENT ADVANCES IN STRUCTURE SOLUTION FROM POWDER DIFFRACTION DATA

2002 ◽  
Vol 16 (01n02) ◽  
pp. 407-414 ◽  
Author(s):  
M. A. NEUMANN ◽  
F. J. J. LEUSEN ◽  
G. E. ENGEL ◽  
S. WILKE ◽  
C. CONESA-MORATILLA
Keyword(s):  
Crystal Structure ◽  
Dft Calculations ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
First Principles ◽  
Crystal Structure Determination ◽  
Powder Diffraction Data ◽  
Recent Advances ◽  
Structure Solution

Crystal structure determination frequently is a prerequisite for the rational understanding of the solid state properties of new materials. Even though single crystal diffractometry is the method of choice when it comes to crystal structure determination, this approach is often impractical because of the difficulties involved in growing single crystals of appropriate size. High quality powder samples, on the other hand, are much easier to obtain. Using direct-space structure solution techniques, increasingly complex crystal structures can nowadays be solved directly from powder diffraction data. Combined with easy-to-use tools for model building and visualization as well as molecular mechanics and first principles Density Functional Theory (DFT) calculations, crystal structure solution from powder diffraction data is becoming a routine task. To illustrate the applicability of direct-space Monte Carlo techniques to the crystal structure solution of organic and inorganic compounds, a variety of structure solutions with the Powder Solve algorithm are presented. Recent advances include the determination of a preferred orientation correction during the structure solution search and the use of parallel tempering, a newly implemented global search algorithm. As a complementary technique, first principles DFT calculations have been used successfully to validate structure solutions and to aid the subsequent Rietveld refinement.

Utilizing organic and organometallic structural data in powder diffraction

2014 ◽  
Vol 29 (S2) ◽  
pp. S19-S30 ◽  
Author(s):  
Jason C. Cole ◽  
Elena A. Kabova ◽  
Kenneth Shankland
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structural Data ◽  
Cambridge Structural Database ◽  
Powder Diffraction Data ◽  
Racemic Form ◽  
Structure Solution ◽  
Structural Database

The Cambridge Structural Database (CSD) is a database of small molecule organic and organometallic crystal structures elucidated using X-Ray and neutron crystallography. The CSD is distributed alongside a system of software (the Cambridge Structural Database System) to academic and industrial users. The system contains a number of applications (in particular DASH, ConQuest, and Mogul) that can be used to aid crystallographers in the solution and refinement of crystal structures from powder diffraction data, and in the interpretation of crystal structure models (in particular, Mercury). This publication uses a racemic form of ornidazole (Z′ = 3) to illustrate the efficacy of DASH in the crystal structure solution from powder diffraction data. Furthermore, numerous features in Mogul and Mercury that aid crystal structure solution and interpretation of crystallographic data are revised. Finally, a review of a new method for using database-derived geometric information directly in structural solution is presented.

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