Comparison of calculated and experimental powder x-ray diffraction patterns of organic materials

The Powder Data File (PDF) contains far fewer organic entries than inorganic ones despite the existence of many more organic compounds. The ready availability of many of the missing organic substances affords their potential inclusion via quality experimental patterns. Considerable expansion of the organic portion of the PDF is also available via computation from the extensive published single crystal literature. Careful comparison of calculated and experimental patterns can be quite useful in resolving problems encounter in patterns from each source and in more fully characterizing ''real-life'' materials. Examples of this interplay are presented, featuring, particularly, explosive compounds, an especially sparsely populated portion of the PDF.