Crystallography structure

B. K. Vainshtein, Modem Crystallography I Fundamentals of Crystals Symmetry and Methods of Structural Crystallography. 2nd ed. Springer, 1994. 

J.V. Smith, Geometrical and Structural Crystallography, Wiley, New York, 1982. 

Numerous reports of other examples of 1 2 Peacock-Weakley complexes are summarized in Table 5. Whereas some of these species have subsequently been confirmed by structural crystallography, many of the cited references report only non structure-specific data such as elemental analyses, IR spectra, magnetic moments, and electrochemistry. 

It should be reemphasized that the above high-symmetry examples refer to isolated molecules and not to crystal structures. Crystallography has, of course, been one of the main domains where the importance of polyhedra has been long recognized, but they are not less important in the world of molecules. 

The types of radiations that are used in structural crystallography are mainly x-rays, neutrons, and electrons. The use of electrons is still difficult for structure determination but can be a useful tool for the detection of structural transitions (see Section X). White or monochromatic x-ray beams can conveniently be obtained from sealed tubes, rotating anode generators, or synchrotron sources [5], with relative flux magnitudes on the order of 1, 10, >100, respectively. The first two x-ray sources are continuous and are generally designed to produce almost monochromatic beams, while synchrotron radiation is pulsed and white. Neutron sources are comparatively much weaker and are either continuous (nuclear reactor) or pulsed (spallation source [6]). 

The foregoing sections have been devoted primarily to structural crystallography and phase-transition studies hereafter we discuss briefly the use of other crystallographic techniques in the study of low-dimensional organic conductors. Our goal is not an exhaustive review but simply to give some leads toward a different approach to these materials. For example, since crystallography is the science of crystals, two of the sections below are on sample size and quality. 

In the 1970s the structural crystallography of molecular compounds was essentially confined to room-temperature structure determinations. The... 

It is of interest to note Tutton s optimistic assesment of Lehmann s definition of monotropism and enantiotropism, pubhshed just prior to the dawn of the age of structural crystallography ... 

Coster, D., Knol, K. S., and Prins, J. A. Unterschiede in der Intensitat der Rbntgenstrahlenreflexion an den beiden 111 Flachen der Zinkblende. [Differences in intensity between the X-ray reflections from the two 111 faces of zinc blende.] Z. Physik 63, 345-369 (1930). English translation Stezowski, J. J. In Structural Crystallography in Chemistry and Biology. (Ed., Glusker, J. P.) pp. 158-160. Hutchinson Ross Stroudsburg, PA, Woods Hole, MA (1981). 

This paper was to have been prepared by Walter C. Hamilton. It is a matter of great sadness to us all that he has been taken from us. Aside from our personal loss, his absence has been a substantial scientific loss to this conference. I cannot feel that I am in any real sense a replacement for him. My paper by no means covers all that Walter Hamilton would have included, in view of his unique position at the forefront of many areas of structural crystallography as well as my own relative detachment from direct technical involvement in crystal-structure determination over the past few years. 

In this brief survey many of the experimental and interpretive aspects of structural crystallography have been covered very lightly or not at all. For further details, the reader is referred to standard texts such as the one by Stout and Jensen.27 A useful guide to the applications of statistics to the interpretation of physical measurements, with particular emphasis on structural crystallography, is provided by Hamilton s excellent book.28 A useful survey of structural crystallography, which parallels this one in some aspects but provides more examples of the interpretation of structural results for organic molecules, has been given by Stewart and Hall.29... 

Obviously some time had to pass, a little more than a decade, before X-ray diffraction had a practical application to micas, but the path had been opened to a new science, structural crystallography, which was immediately incorporated into the older science of mineralogy. 

While Pasteur was able to deduce many important conclusions using optical crystallography as his main tool, structural crystallography has the ability to go much further. It has been established that tartaric acid contains two centers of dissymmetry, with the naturally obtained optically active acid having the (i ,i )-configuration [23], En-... 

Miller indices are important to the crystallisation scientist as they provide a link between the modem structural crystallography of X-ray diffraction and classical morphological crystallography of shape and habit. This allows the process chemist or pharmaceutical scientist to link the internal molecular structure to the chemical functionality of the external surface stracture. Figure 8.2 (bottom right) shows the observed morphology for D-mannitol with the Miller indices labelled. 

Belov NV (1986) Essays on structural crystallography. Nauka, Moscow (in Russian)... 

Vainshtein, B.K. (1996) Modern Crystallography 1 Fundamentals of Crystals. Symmetry, and Methods of Structural Crystallography. Springer, Heidelberg. 

Gilli P, Pretto L, Gilli G (2007) PAIpK equalization and the prediction of the hydrogen-bond strength a synergism of classical thermodynamics and structural crystallography. J Mol Struct 844-845 328-339... 

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