Quantitative Structure Descriptors for Standard and Modulated Crystals: Crystal Structure Systematics, Interpretation, and Prediction

Crystal structure analysis becomes more and more an automated task with continuing methodological improvements resulting in an exponential growth in the number of known structures. Yet, the chemical understanding of the structures lacks behind, partly due to highly specific ways of structure description, dominated by subjective choices, hardly transferable from one case to another. Thus, there is a clear demand for objective and quantitative structural descriptors. Based on our experience with descriptors taken from uniform distribution theory the aim of this project is to develop new quantitative structure descriptors and apply them to the generic case of complex, especially modulated crystal structures. The descriptors should explain the subtle structural phenomena in modulated crystals, and be used to establish novel structure-property relationships for these compounds. For this purpose, we will include a data mining approach to crystal structure databases for compounds of technological importance, complemented with crystal structures measured in the applicant's laboratory. We aim for the development of novel quantitative structure descriptors for molecules and crystals useful for their classification and in establishing structure-property relationships, including the exploration of crystallographic databases and the validation of X-ray diffraction data.