Crystal structure determination by combined synchrotronpowder X-ray diffraction and crystal structure prediction: 1 : 1 l-ephedrined-tartrate

CrystEngComm ◽  
2013 ◽  
Vol 15 (10) ◽  
pp. 1853-1859 ◽  
Author(s):  
Han Wu ◽  
Matthew Habgood ◽  
Julia E. Parker ◽  
Nik Reeves-McLaren ◽  
Jeremy K. Cockcroft ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Structure Prediction ◽  
Crystal Structure Determination ◽  
Crystal Structure Prediction ◽  
X Ray Diffraction ◽  
X Ray

New similarity index for crystal structure determination from X-ray powder diagrams

2005 ◽  
Vol 38 (6) ◽  
pp. 861-866 ◽  
Author(s):  
Detlef Walter Maria Hofmann ◽  
Ludmila Kuleshova
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Structure Prediction ◽  
Similarity Index ◽  
Crystal Structure Determination ◽  
Crystal Structure Prediction ◽  
X Ray ◽  
Organic Pigments ◽  
Structure Solution ◽  
Similarity Indices

A new similarity index for automated comparison of powder diagrams is proposed. In contrast to traditionally used similarity indices, the proposed method is valid in cases of large deviations in the cell constants. The refinement according to this index closes the gap between crystal structure prediction and automated crystal structure determination. The opportunities of the new procedure have been demonstrated by crystal structure solution of un-indexed powder diagrams of some organic pigments (PY111, PR181 and Me-PR170).

scholarly journals Crystal structures of two furazidin polymorphs revealed by a joint effort of crystal structure prediction and NMR crystallography

2020 ◽  
Vol 76 (3) ◽  
pp. 322-335 ◽  
Author(s):  
Marta K. Dudek ◽  
Piotr Paluch ◽  
Edyta Pindelska
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Structure Determination ◽  
Structure Prediction ◽  
Structural Features ◽  
Crystal Structure Determination ◽  
Crystal Structure Prediction ◽  
Crystal Forms ◽  
Space Groups ◽  
Nmr Crystallography

This work presents the crystal structure determination of two elusive polymorphs of furazidin, an antibacterial agent, employing a combination of crystal structure prediction (CSP) calculations and an NMR crystallography approach. Two previously uncharacterized neat crystal forms, one of which has two symmetry-independent molecules (form I), whereas the other one is a Z′ = 1 polymorph (form II), crystallize in P21/c and P 1 space groups, respectively, and both are built by different conformers, displaying different intermolecular interactions. It is demonstrated that the usage of either CSP or NMR crystallography alone is insufficient to successfully elucidate the above-mentioned crystal structures, especially in the case of the Z′ = 2 polymorph. In addition, cases of serendipitous agreement in terms of 1H or 13C NMR data obtained for the CSP-generated crystal structures different from the ones observed in the laboratory (false-positive matches) are analyzed and described. While for the majority of analyzed crystal structures the obtained agreement with the NMR experiment is indicative of some structural features in common with the experimental structure, the mentioned serendipity observed in exceptional cases points to the necessity of caution when using an NMR crystallography approach in crystal structure determination.

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

Characterization of Complicated New Polymorphs of Chlorothalonil by X-ray Diffraction and Computer Crystal Structure Prediction

2004 ◽  
Vol 126 (22) ◽  
pp. 7071-7081 ◽  
Author(s):  
Maryjane Tremayne ◽  
Leanne Grice ◽  
James C. Pyatt ◽  
Colin C. Seaton ◽  
Benson M. Kariuki ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structure Prediction ◽  
Crystal Structure Prediction ◽  
X Ray Diffraction ◽  
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.

Die Kristallstruktur von [Na(12-Krone-4)2+]2Se82- · (Se6, Se7) / The Crystal Structure of [Na(12-Crown-4)2+]2Se82- · (Se6, Se7)

1991 ◽  
Vol 46 (10) ◽  
pp. 1287-1292 ◽  
Author(s):  
Rüdiger Staffel ◽  
Ulrich Müller ◽  
Andreas Ahle ◽  
Kurt Dehnicke
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Title Compound ◽  
Crystal Structure Determination ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Disordered Structure

The title compound was prepared from sodium polyselenide and 12-crown-4 in DMF solution in the presence of cerium(III)chloride in the form of black needles. The crystal structure determination by X-ray diffraction shows a partially disordered structure, in which the anionic units Se82- · Se7 and Se82- · Se6 are present in the ratio 0.72/0.28. These units are associated to layers parallel to (100); the layers alternate with pseudohexagonal layers of [Na(12-crown-4)2]+ ions. Space group P1̅, Z = 2, 3903 observed unique reflections, R = 0.114, wR= 0.084. Lattice dimensions at -65°C: a = 1247.9(3), b = 1367.8(8), c = 1660(1) pm, α = 94.65(5), β = 98.94(3), γ = 91.10(3)°.

Azine bridged silver coordination polymers: Powder X-ray diffraction route to crystal structure determination of silver benzotriazole

2006 ◽  
Vol 179 (4) ◽  
pp. 1053-1059 ◽  
Author(s):  
Manju Rajeswaran ◽  
Thomas N. Blanton ◽  
David J. Giesen ◽  
David R. Whitcomb ◽  
Nicholas Zumbulyadis ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Coordination Polymers ◽  
Structure Determination ◽  
Crystal Structure Determination ◽  
X Ray Diffraction ◽  
X Ray
Sign in / Sign up

Export Citation Format

Share Document