CRUNCH is a direct methods structure solution program optimised for equal atom structures, though now with improved handling of heavy atom structures. CRUNCH has a reputation for handling difficult structures that can fail to solve with other software. CRUNCH is the program that solved the C28H37O6N problem posted by John Huffman on the sci.techniques.xtallography newsgroup in April 1994 (under the topic of Subject: Want to solve a structure?). It only runs on UNIX (including LINUX) but is very easy to install and get running. 5th March 2003 Crunch accountment From R.A.G. de Graaff: Dear All, Al long last some news. I do hope you are happy to know that I'm still working on maintenance of the system. I have repaired some errors in the section which calculates E-values, using the programs levy.f and eval.f (Blessing and Levy). Creating E-values this way is possible by typing: "crunch code blessing" before trying to solve the structure. Removing the errors should imrove the performance of the system. More serious errors in the program, concerned with the handling of spacegroups such as R 3 2, indexed on rhombohedral axes, have been repaired. If you have encountered problems using the option blessing or if you have many compounds crystallising in space groups such as R 3 2 it might be well worth your while to download Crunch and install the latest version. Yours, Rag de Graaff. RAG de Graaff Leiden Institute of Chemistry Department of Biophysical Structural Chemistry Gorlaeus Labs. PO Box 9502 2300 RA Leiden The Netherlands http://chema110.leidenuniv.nl:80/~rag/ [email protected] Note that if you only have windows running on your PC, there is a page on the CCP14 site on how to setup a PC to dual boot Windows or Redhat Linux. as well as a page on setting up a PC to dual boot Windows or FreeBSD Crunch is trivial to use from within the Platon/System Suite based around Shelx style files (activated at the click of a single button). The complete System S install instructions are provided on the web.

Obtaining CRUNCH