At 16:28 26/02/2004, Jon Wright wrote: >Broadly, this means "crappy" data with a chemically unreasonable model can sometimes >give much better figures of merit than a good structure with "good" data.
True, with enough parameters you can fit an elephant, but the calculated errors in your structure co-ordinates should reflect the fact that they are poorly determined (unless you have introduced too many constraints, which can make calculated errors meaningless). A low R-factor is not in itself a guarantee that you have a good structure - you need to look at the bond lengths and atom co-ordination, calculate Brown-Shannon valence sums where applicable etc... Alan Hewat, ILL Grenoble, FRANCE <[EMAIL PROTECTED]> fax (33) 4.76.20.76.48 (33) 4.76.20.72.13 (.26 Mme Guillermet) http://www.ill.fr/dif/AlanHewat.htm ___________________________________________________________
