scispace - formally typeset
JournalISSN: 0108-2701

Acta Crystallographica Section C-crystal Structure Communications 

About: Acta Crystallographica Section C-crystal Structure Communications is an academic journal. The journal publishes majorly in the area(s): Crystal structure & Hydrogen bond. It has an ISSN identifier of 0108-2701. Over the lifetime, 19918 publication(s) have been published receiving 122162 citation(s).
Papers
More filters

Journal ArticleDOI
TL;DR: New features added to the refinement program SHELXL since 2008 are described and explained.
Abstract: The improvements in the crystal structure refinement program SHELXL have been closely coupled with the development and increasing importance of the CIF (Crystallographic Information Framework) format for validating and archiving crystal structures. An important simplification is that now only one file in CIF format (for convenience, referred to simply as `a CIF') containing embedded reflection data and SHELXL instructions is needed for a complete structure archive; the program SHREDCIF can be used to extract the .hkl and .ins files required for further refinement with SHELXL. Recent developments in SHELXL facilitate refinement against neutron diffraction data, the treatment of H atoms, the determination of absolute structure, the input of partial structure factors and the refinement of twinned and disordered structures. SHELXL is available free to academics for the Windows, Linux and Mac OS X operating systems, and is particularly suitable for multiple-core processors.

21,137 citations


Journal ArticleDOI
TL;DR: The SQUEEZE method is documents as an alternative means of addressing the solvent disorder issue and conveniently interfaces with the 2014 version of the least-squares refinement program SHELXL, and many twinned structures containing disordered solvents are now also treatable by SQUEEze.
Abstract: The completion of a crystal structure determination is often hampered by the presence of embedded solvent molecules or ions that are seriously disordered. Their contribution to the calculated structure factors in the least-squares refinement of a crystal structure has to be included in some way. Traditionally, an atomistic solvent disorder model is attempted. Such an approach is generally to be preferred, but it does not always lead to a satisfactory result and may even be impossible in cases where channels in the structure are filled with continuous electron density. This paper documents the SQUEEZE method as an alternative means of addressing the solvent disorder issue. It conveniently interfaces with the 2014 version of the least-squares refinement program SHELXL [Sheldrick (2015). Acta Cryst. C71. In the press] and other refinement programs that accept externally provided fixed contributions to the calculated structure factors. The PLATON SQUEEZE tool calculates the solvent contribution to the structure factors by back-Fourier transformation of the electron density found in the solvent-accessible region of a phase-optimized difference electron-density map. The actual least-squares structure refinement is delegated to, for example, SHELXL. The current versions of PLATON SQUEEZE and SHELXL now address several of the unnecessary complications with the earlier implementation of the SQUEEZE procedure that were a necessity because least-squares refinement with the now superseded SHELXL97 program did not allow for the input of fixed externally provided contributions to the structure-factor calculation. It is no longer necessary to subtract the solvent contribution temporarily from the observed intensities to be able to use SHELXL for the least-squares refinement, since that program now accepts the solvent contribution from an external file (.fab file) if the ABIN instruction is used. In addition, many twinned structures containing disordered solvents are now also treatable by SQUEEZE. The details of a SQUEEZE calculation are now automatically included in the CIF archive file, along with the unmerged reflection data. The current implementation of the SQUEEZE procedure is described, and discussed and illustrated with three examples. Two of them are based on the reflection data of published structures and one on synthetic reflection data generated for a published structure.

2,100 citations



Journal ArticleDOI
Abstract: ZnS cristallise dans P6 3 mc avec a=8227 et c=6,2607 A, Z=2; affinement jusqu'a R=0,017. ZnO cristallise dans P6 3 mc avec a=3,2501 et c=5,2071 A, Z=2 affinement jusau'a R=0,012. Les atomes Zn occupent la position speciale 2(b) avec les coordonnees 1/3, 2/3, Os et O occupent egalement la position speciale 2(b) avec les coordonnees 1/3, 2/3, u. Pour ZnS, u=0,3748 et pour ZnO, u=0,3817. Dans les deux cas, u et c/a se conforment a la correlation comme entre ces parametres

358 citations


Journal ArticleDOI
TL;DR: Pentacene, C(22)H(14), crystallizes in different morphologies characterized by their d(001)-spacings of 14.1 and 14.5 A d-spacing morphologies grown by vapour transport and from solution.
Abstract: Pentacene, C22H14, crystallizes in different morphologies characterized by their d(001)-spacings of 14.1, 14.5, 15.0 and 15.4 A. We have studied the crystal structure of the 14.1 and 14.5 A d-spacing morphologies grown by vapour transport and from solution. We find a close correspondence between the 14.1 A structure reported by Holmes, Kumaraswamy, Matzeger & Vollhardt [Chem. Eur. J. (1999), 5, 3399–3412] and the 14.5 A structure reported by Campbell, Monteath Robertson & Trotter [Acta Cryst. (1961), 14, 705–711]. Single crystals commonly adopt the 14.1 A d-spacing morphology with an inversion centre on both mol­ecules in the unit cell. Thin films grown on SiO2 substrates above 350 K preferentially adopt the 14.5 A d-spacing morphology, with a slightly smaller unit-cell volume.

294 citations


Network Information
Related Journals (5)
Journal of Chemical Crystallography

4.3K papers, 24.9K citations

94% related
Acta Crystallographica Section B-structural Science

3.1K papers, 120.1K citations

91% related
Acta Crystallographica Section E-structure Reports Online

37.9K papers, 78.8K citations

91% related
Polyhedron

19.1K papers, 304K citations

90% related
Performance
Metrics
No. of papers from the Journal in previous years
YearPapers
2021100
2020141
2019212
2018232
2017174
2016160

Top Attributes

Show by:

Journal's top 5 most impactful authors

Christopher Glidewell

469 papers, 1.5K citations

John N. Low

263 papers, 889 citations

Justo Cobo

221 papers, 527 citations

Hoong-Kun Fun

208 papers, 777 citations

Ricardo Baggio

174 papers, 624 citations