Crystal Structure Determination - Massa, Werner

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Résumé :
To solve a crystal structure means to determine the precise spatial arrangements of all of the atoms in a chemical compound in the crystalline state. This knowledge gives a chemist access to a large range of information, including connectivity, conformation, and accurate bond lengths and angles. In addition, it implies the stoichiometry, the density, the symmetry and the three dimensional packing of the atoms in the solid. Since interatomic distances are in the region of100-300 pm or 1-3 A, 1 microscopy using visible light (wavelength ? ca. 300-700 nm) is not applicable (Fig. l. l). In 1912, Max von Laue showed that crystals are based on a three dimensionallattice which scatters radiation with a wavelength in the vicinity of interatomic distances, i. e. X -rays with ? = 50-300 pm. The process bywhich this radiation, without changing its wave? length, is converted through interference by the lattice to a vast number of observable reflections with characteristic directions in space is called X-ray diffraction. The method by which the directions and the intensities of these reflections are measured, and the ordering of the atoms in the crystal deduced from them, is called X-ray struc? ture analysis. The following chapter deals with the lattice properties of crystals, the starting point for the explanation of these interference phenomena. Interatomic distances Crystals . . . . . . . . . .

Biographie:
Prof. Dr. Werner Massa, Universit?t Marburg...

Sommaire:
Highly praised for its practical and insightful approach, this textbook gives a concise introduction to modern crystal structure determination, emphasizing both the crystallographic background and how to actually perform it. The theoretical sections?stress?comprehension, supported by many illustrations, than to a rigorous derivation of?the mathematics.?Key measuring techniques, including the use of modern area detectors, 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 wisely judge the quality of results. The second edition has been completely updated and extended, especially the chapter on structural interpretation. From the reviews of the first edition - Distinguished by its attention to the practicalities of working with real crystals...a lucid and relatively concise account of modern crystal structure solution ...valuable to anyone who has an interest in crystal structure refinement. The Geological Journal Details at great length the inherent pitfalls and errors that one may encounter when calculating crystal structures using new software programs. The author does an excellent job of describing these errors and ways to recognize them when they appear in your calculations... Mineralium Deposita...