Structure determination from powder diffraction data: past, present and future challenges

Structural information is crucial for understanding and tailoring the materials properties. When the materials are available only in the polycrystalline form, powder diffraction is the method of choice for structure determination. Compared to the single crystal data, the powder pattern contains less information due to the overlap problem and the reduction of the information content is even larger if only the low resolution data are available. Several data analysis approaches are available to address this problem, including reciprocal, direct and dual space methods. They are discussed and illustrated by a number of examples, including cases where other techniques, such as IR and NMR spectroscopy, electron microscopy and crystal-chemical knowledge have to be applied to solve the structure.