chem cryst
CRYSTALS Software
University of Oxford

Crystals

The CRYSTALS software package for single crystal X-ray structure refinement and analysis consists of CRYSTALS, Cameron and specially recompiled versions of SIR92 and SHELXS. Download CRYSTALS here.

SIR and SHELXS provide the direct methods. CRYSTALS and Cameron provide everything else including

• built-in guidance and validation using The GUIDE.
• import and data reduction from many sources: SHELX/XPrep/WinGX format .ins/.hkl files, CAD4 .dat files, KappaCCD import.cif.
• automatic hydrogen atom placement using combined geometric/difference Fourier placement.
• interactive graphical model of the structure
• sophisticated refinement with constraints and restraints
• various reflection weighting schemes
• graphical analysis of data, results and residuals
• refinement of twinned data and discovery of unnoticed twin-laws using the ROTAX procedure
• fourier maps and contour plots. Output to contour, MCE3D, MapView and ASCII formats.
• Acta Cryst friendly CIFS and publication tables
• colour thermal ellipsoid plots in Cameron. Output in WMF, postscript, encapsulated postscript, CHIME formats or print directly to a Windows printer.
• powerful atomic and structural parameter editor

A project is well underway (and included in the distributed version) that aims to provide novice users of CRYSTALS with the expert decision-making tools required for undertaking unsupervised structure determination.

We believe that X-ray structure determination should be available as a routine analytical technique for synthetic chemists. X-ray crystal structures provide results that are very easy to understand compared to other analytical techniques, and with modern hardware the entire experiment and analysis can be completed in a morning.

Over the last year feedback from users has enabled us to significantly improve the ease of use and features of the program.
The decision-making system and validation tools are written in CRYSTALS' own macro language, SCRIPTS, so that they can be modified to accommodate expert knowledge without users needing to become expert programmers or install compilers.

The current CRYSTALS software package is freely distributed over the Internet to academic institutions.

Several conversion utitlities are also provided:

• SXtoCRY converts SHELX.INS or .RES files to Crystals format input files.
• RC93 prepares data for Crystals from a CAD4 diffractometer.
• DIPin prepares data for Crystals from an Nonuis DIP2000 diffractometer.
• KCCDin prepares data for Crystals from an Nonuis Kappa CCD diffractometer.
• CSD2CRY converts CSD files to Crystals format input files.
• CIF2CRY converts CIFs to Crystals format input files.

The programs are currently available for the Microsoft Windows 95/98/Me range and the NT/2000/XP range of operating systems.

A full implementation with graphical interface should soon be available for Linux. Any programmers wishing to help with debugging the Linux port should get in touch...

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