The discovery of the homometry of X-ray diffraction dates back to the 1930s and shows the ambiguity in structure characterization purely from diffraction technologies. Since then, there has only been limited discussion on this topic with reference to several real structures and an efficient method for finding homometric structures for a known three-dimensional structure is still lacking today. In this work, a method was developed to create a set of structures with the same interatomic distances as an original structure, which can then be identified as powder X-ray diffraction or single-crystal X-ray diffraction homometric structures. This method was applied to the Inorganic Crystal Structure Database (ICSD) and homometric structures for 37 reported structures were found. Also it was found that homometric structures are encountered frequently in solving crystal structures when building initial models with only heavy atoms, which indicates that special caution is needed in interpreting XRD data with heavy-atom methods.
Keywords: X-ray diffraction; crystal structure; homometric structure; structure determination.