CHECKLIST FOR THE DESCRIPTION OF INCOMMENSURATE MODULATED CRYSTAL-STRUCTURES - REPORT OF THE INTERNATIONAL-UNION-OF-CRYSTALLOGRAPHY COMMISSION-ON-APERIODIC-CRYSTALS

One of the terms of reference published in 1992 (Acta Cryst. A48, 922- 946) in the report of the (at that time) Ad Interim Commission on Aper iodic Crystals was 'to co-operate with other Commissions of the IUCr i n establishing adequate guidelines and standards for articles to be pu blished in IUCr journals reporting structural investigations of aperio dic crystals and theoretical investigations of aperiodic patterns'. It was soon recognized by the Commission that the establishment of a che cklist for the publication of incommensurately modulated structures wa s perhaps the most urgent task. One of the first attempts to address t he problem of publishing incommensurate structures was presented durin g a discussion organized in 1991 in Leikeitio, Spain, in a workshop de dicated to methods of structural analysis of modulated structures and quasicrystals. Since this meeting, the work of the Commission progress ed interactively by numerous exchanges on the occasions of internation al meetings and mostly by electronic correspondence. The Checklist was accepted in 1994 by the Executive Committee of the IUCr. The opinion of the Commission on Journals was also requested and, following the co mments of its members, the Checklist has been completed with an exampl e of an incommensurate crystal structure illustrating each specific it em that is required in the Checklist.