COMCIFS reports

COMCIFS is the committee appointed to maintain the Crystallographic Information File (CIF). It includes Subcommittees of the Dictionary Maintenance Groups, the Dictionary Review Committee, the Publicity Committee, the Software Development Committee and the dictionary Definition Language Committee. Currently under final review are the modulated structure dictionary (msCIF) and a dictionary containing basic symmetry concepts used in crystallography (symCIF). Draft dictionaries for electron density (rhoCIF), magnetic structures (magCIF) and small angle scattering (sasCIF) were submitted to the Dictionary Review Committee and are currently undergoing revision to bring them into conformity with CIF standards. Protocols for merging two or more dictionaries into a larger virtual dictionary and developing the necessary software for manipulating CIFs are currently major concerns.

Most of the software currently available for CIF is in the form of toolboxes to help others write CIF applications. The program enCIFer, to be released by the Cambridge Crystallographic Data Centre in late 2001, has many features that crystallographers will find useful. These include a browser that provides clear error markup, an alphabetic view of data names, data entry panes containing the dictionary definitions, buttons for the special character sequences frequently used in CIF text, spreadsheet loop displays, text searching, a text editing window, user templates and a crystal structure visulizer. Several members of COMCIFS are working on the text for Volume G of International Tables for Crystallography, the volume that describes the CIF standards. As a result of the efforts of J. Westbrook, D. Greer and others, mmCIF has been recognized by the Object Management Group as providing the Common Object Request Broker Architecture standard (CORBA) for the exchange of macromolecular information between databases.

An exciting proposed extension for CIF is a dictionary of Relational Expression Language (dRel) which will provide algorithmic expressions that allow values for each item in the dictionary to be derived from other items, e.g., the calculation of the density from the cell mass and cell volume. A preliminary account of dRel has been given by Spadaccini, Hall and Castledean (2000) J. Chem. Inf. Comput. Sci. 40, 1289-1301.