22卷6期结构化学（.PDF

22 卷6 期 结 构 化 学 （JIEGOU HUAXUE ） Vol. 22, No. 6 2003. 11 Chinese J. Struct. Chem. 691~699 Revising Space Groups from Simulated SHELX fcf Structure Factors. More Examples of Incorrect Space Groups, an Example of a Chemically-Incorrect Structure and the Special Case of P 1 to Pî Revisions Ng Seik Wenga① XIE Zhao-Xiongb a (Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia) b (State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University , Xiamen 361005, China) ABSTRACT The structure factors of any crystal structure can be simulated from its atomic coordinates (and temperature factors) in a SHELXL-97 run on a dummy hkl in which only the scale factor is refined. The squares of the structure factors are retrieved from the fcf , and such simulated data are used in the revision of the space groups of several incorrectly-refined crystal structures. Two cases, a P 1 to P 1 revision and a chemically-incorrect structure that is refined in a correct space group, are discussed. Keywords: space-group correction, crystal structure revision, simulated structure factors 1 INTRODUCTION SHELXL-97 run on a dummy hkl as the run gene- rates an fcf file[7], which contains the desired values. Although the incorrect assignment of the space The hkl-F2 of seven incorrectly-refined crystal groups of