Inter-esting hurdles in the solution of pharmaceutical crystal structures using powder diffraction data.

Although solving and refining a crystal structure using synchrotron powder diffraction data can be routine, many problems present features which make the process more difficult. These include difficulty in indexing, incorrect or approximate symmetry, and chemically unreasonable models (poor conformations, incorrect compounds). Examples of each of these 'inter-esting' features are provided, as well as the methods used for recognizing and overcoming them. Raw data and GSAS-II project files are provided for all of the examples.