Optical crystallography

These operations are performed faster than it takes to describe them, and are usually sufficient to characterize a material. The specific steps to perform each of the above may be found in any textbook on optical crystallography. 

N.H. Hartshorne and A. Stuart, Practical Optical Crystallography, Arnold, London, 2nd edn., 1969 Crystals and the Polarizing Microscope, Arnold, London, 4th edn., 1970. 

E. E. Wahlstrom, Optical Crystallography, 4th ed., John Wiley Sons, New York, 1969. 

Fig. 6.8. (a) The spherical projection of the faces of a crystal. The numbers indicate the Miller indices of the corresponding planes, (b) Photomicrograph of a polycrystalline brass. (Reprinted with permission from Elizabeth A. Wood in Crystals and Light. An introduction to Optical Crystallography, 2nd ed., Dover, 1977, Plate lll(2) and Fig. 4.5.)... 

Madison, Wisconsin (1943) 25)E.E.Walstrom, "Optical Crystallography , Wiley, NY (1943) 26)A.F.Wells, "Structural Inorganic Chemistry , Clarendon Press, Oxford (1945) 27)C-... 

There are a number of additional sources for consultation on information on polymorphism of particular compounds. From 1948 to 1961, McCrone edited a regular column in Analytical Chemistry entitled Crystallographic Data , in which were published the details on crystal growth, physical properties, and polymorphic behaviour of approximately 200 compounds. The series was undertaken at the time because optical crystallography is neglected as an analytical tool because too few compounds have been described , and with the desire to ... initiate a process which [would] enable a group of crystallographers to complete the tabulation of crystal data for most... 

FIGURE 2.13 (cont d). An equatorial plane (plane of projection) is selected, and the points where these lines to the pole touch the equatorial plane are noted (labeled 1 to 5), (c) The points of intersection with the equatorial plane are joined by lines or arcs, (d) The resulting diagram, viewed on the equatorial plane, shows the symmetry of the crystal, cubic in this case, (Courtesy Ernest E. Wahlstrom and John Wiley Sons, Inc. From Wahlstrom, E. E. Optical Crystallography. 5th edn, John Wiley New York, Chichester, Brisbane, Toronto (1979). John Wiley Sons, Inc.)... 

Wood, E. A. Crystals and Light. An Introduction to Optical Crystallography. Van Nostrand New York (1977). 

Shubnikov, A. V. Principles of Optical Crystallography. English translation (from the Russian) Consultants Bureau New York (1960). 

Yu, L. (2002). Color changes caused by conformational polymorphism optical crystallography, single-crystal spectroscopy, and computational chemistry. J. Phys. Chem. A 106, 544-550. 

Corresponding isomers of the other anions of this series (Table 1) are expected. The isolable forms of As2Wi8062 and P2Moi80<52 have the B-structure (optical crystallography see references in (100)). A second form of As2Wi8062 could not be obtained (101). Evidence for unstable forms of the X2Moi8062 ions in solution has been given (102). 

Wahlstram, E. Optical crystallography. New York John Wiley and Sons, 1951. 

An extremely important tool for the characterization of polymorphs and solvates is that of microscopy, since the observable habits of differing crystal structures must necessarily be different and therefore useful for the characterization of such systems [27]. Common sense would dictate that the visual observation of such materials would immediately follow an x-ray crystallographic study, which would in principle make the science of optical crystallography [28-30] an essential aspect of any program of study. A review of crystallography from the pharmaceutical viewpoint is available [31]. 

N. H. Hartshome, and A. Stuart, Pradical Optical Crystallography, Elsevier, New York, 1964. 

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-... 

Table 8.1 This table, for the two polymorphic forms of paracetamol, illustrates the type of data that can be collected using optical crystallography [11]...

Recrystallization experiments frequently yield crystals having different shapes and morphologies which are not necessarily different polymorphs. For example, Figs 8.2 and 8.3 show crystals of p-estradiol with distinctly different shapes but are, in fact, the same polymorph. The morphology differences are due to different crystallization solvents. It is important then to have some microscopical technique that allows one to distinguish between polymorphs. Optical crystallography, thermal microscopy and microspectroscopy have this ability. 

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