Refinement by atomicity

Abstract

Abstract Besides the commonly employed refinement by minimization of the R factor, there is refinement by atomicity. These two refinements lead to two refined structures. Both structures are reasonable and close to each other. The differences between the results of these two refinements are significant. Refinement by atomicity is used as a supplement to refinement by minimization of R factor. For any crystal structure determined by minimization of R factor or other method, with all atoms determined and occupancy of each site equal to 1, in principle, refinement by atomicity should be applied. The purpose is to improve the atomic coordinates. It remains for the X-ray crystallographers to devise a procedure to obtain an improved structure from these two refined structures. The procedure can then be applied to all crystal structures reported in the literatures, or will be published in the future. This means that most articles in X-ray crystallography need to be improved. Many articles and books in other disciplines directly or indirectly contain or use structural informations, such as bond lengths and bond angles, obtained in X-ray crystallography. All these articles and books need to be revised.