CHEM 416 - X-ray Crystallography

This textbook gives a concise introduction to modern crystal structure determination, emphasizing both its theoretical background and the way it is actually carried out. The theoretical sections are supported by many illustrations, and emphasise good understanding rather than rigorous mathematics. The most important data collection techniques, and the methods of data reduction, structure solution and refinement are discussed from a practical point of view. Many tips and insights help readers to recognize and avoid possible errors and traps, and to judge the quality of results. The second edition has been considerably updated, especially the chapter on experimental methods, which is now mainly concerned with modern data collection using area-detectors.

This text focuses on the practical aspects of crystal structure analysis, and provides the necessary conceptual framework for understanding and applying the technique. By choosing an approach that avoids undue emphasis on the mathematics involved, the book gives practical advice on topics such as growing crystals, solving and refining structures, and understanding and using the results. The technique described is a core experimental method in modern structural chemistry, and plays an ever more important role in the careers of final-year undergraduates, graduate students, postdoctoral and academic staff in chemistry.

(Print) Closely follows an actual structural determination. After some introductory material on the nature of x-rays, the diffraction process, and the internal geometry of crystals, the selection and preparation of a crystal are considered. Techniques of measuring raw x-ray data are covered, plus their reduction into a useable form. The second part discusses both traditional and novel methods of solving the ``phase'' problem, the principal difficulty in x-ray structure determination. The third part considers how to extract the most information from the data and how to evaluate its reliability. Finally, there is a discussion of sources of error in practice and interpretation.

Crystal Structure Refinement is a mixture of textbook and tutorial. As A Crystallographers Guide to SHELXL it covers advanced aspects of practical crystal structure refinement, which have not been much addressed by textbooks so far. After an introduction to SHELXL in the first chapter, a brief survey of crystal structure refinement is provided. Chapters three and higher address the various aspects of structure refinement, from the treatment of hydrogen atoms to the assignment of atom types, to disorder, to non-crystallographic symmetry and twinning. One chapter is dedicated to the refinement of macromolecular structures and two short chapters deal with structure validation (one for small molecule structures and one for macromolecules). In each of the chapters the book gives refinement examples, based on the program SHELXL, describing every problem in detail. It comes with a CD-ROM with all files necessary to reproduce the refinements.

Crystallography and structure theory have recently received increasing interest due to their role in understanding biological structures, high-temperature superconductors, and effects on mineral properties related to changes in temperature and pressure. This book offers a comprehensive account of the wide range of crystallography in many branches of science. The fundamentals, the most frequently used procedures and experimental techniques are all described in a detailed way. A number of appendices are devoted to more specialist aspects. The book is an updated and fully revised new edition with emphasis on the wide range of topical applications and current areas of research. Ample illustrations help clarify the subject matter. To provide a better understanding of the basics of crystallography, a compact disk has been added to this new edition, offering the facilities of modern graphics to simulate experiments, show complex images, and provide a number of exercises.