1) We are refining an organic structure against synchrotron powder data using TOPAS4. The fitting is pretty good in terms of R factors and molecular geometry. However, we find that there are some unusual (I believe, wrong) intermolecular distances in the model. For instance, O...H-C distance (from O to C) is about 2.9, and O...O distance is about 3 Ang. Indeed, these distances are not extremely bad. However, according to the chemical environment, they are not supposed to be so short. In Shelx (single crystal software), it is easy to restrain such intermolecular distance, but we do not know how to do it in TOPAS. How do you refine your structures with restraints in TOPAS or other software?
2) The CIF produced by TOPAS is rather brief, which needs a lot of editing for publication. I wonder what software you use for this purpose? Is there any publication or book or manual about the best practice of reporting the CIF from powder data? Thank you for your input. Best, Tony -- Chunhua Tony Hu, Ph.D X-ray Crystallographer New York University, Department of Chemistry 357A Brown Building, 29 Washington Place Phone: 212-998-8769 (office) 212-998-8298 (lab) Fax: 212-995-4475 Email: [email protected] http://chemistry.fas.nyu.edu/object/chem.sif.xdf http://chemistry.fas.nyu.edu/object/tonyhu.html
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