The Good, the Bad and The Ugly: Publishing Crystal Structures in Dalton. A. Guy Orpen, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK

Crystal structure determinations are ubiquitous in the modern chemical literature. Their role varies from identification of a new product arising from a synthetic investigation to charge density analysis based on extensive and detailed data collection and analysis. In this lecture consideration will be given to these roles, publication of crystal structure determinations in the chemical literature and the function of the crystallographic community in the process.

In Dalton, papers are accepted or rejected on the basis of the chemistry they report, and "chemistry" is defined so as to include synthetic and structural aspects of the subject. Therefore crystal structure determinations must be judged in that light and the key question is: does the structure analysis support the chemical conclusions drawn from it? Assuming that they do so, the structure determinations submitted can be loosely divided into three categories: the good, the bad and the ugly. These are respectively: the structures that are both correct and precise; those that are incorrect or inaccurate; and those that are not precise but are accurate. The first two categories are not usually troublesome in the sense that there is a fair degree of consensus as to what we mean by a good structure, and no doubt that if, for example, the space group is misassigned a correction is required. It is the third class that causes the most soul-searching among referees and authors. It is clear that there are many structure determinations now being carried out (and increasingly being reported) that are "poor" in terms of R factors or precision of bond lengths etc., but that nevertheless carry substantial amounts of useful chemical and structural information. These are the ugly children of crystallography - they may not be pretty but someone loves them.

The roles of crystallographers in their capacities as journal referees, authors and editors in the successful application of crystallography in the chemical literature will be considered.