Results of X-Ray Analysis

Allmann and Kawada and Allmann carried out X-ray analysis on bis-fN-ethyl-benzthiazole]-phosphamethin-cyanine perchlorate 6b and bis-[N-ethyl-quinoline]-phosphamethin-cyanine perchlorate 7b. In 6b the two heterocycles lie roughly in the same plane. The C—P—C bond angle is 104,6°. The P-C bond lengths, 1,754 and 1,757 be regarded as identical, proving that the C-P-C bond network is 

We have to thank Prof. Dr. W. v. Philipsbom, University of Zurich, for the C-NMR-data and helpful discussion. 

Different results were obtained for 7b. Here steric hindrance causes the two ring systems to be twisted 60° out the common plane. The C-P-C bond angle is only 100,4°, the P-C bond lengths are no longer identical and both are longer than in 6b. To our knowledge, no comparable data on methin- or azamethin-cyanines have been reported (Fig. 4 and 5). 

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Results of X-ray analysis of complexes of alkali- and ammonium ions with valinomycin /36-37 and the macrotetrolide antibiotics 2 to 63H 42 support this reasoning. For this idealized situation the Equations IIA to IIC (Table II) reduce to 33... 

NazO/A Z203 Si02/A Z2O3 Results of X-Ray Analysis 9/9... 

Table 1 gives composition, structural and textural characteristics of the catalysts. The evolution of the BET surface areas with the chromium content as well as the results of X ray analysis of the samples pretreated in air at 410°C. 

The consequences of intermolecular interactions are of importance when considering the results of X-ray analysis of crystals the apparent deviations from planarity of molecules having no obviously overcrowded atoms may be wholly caused by crystal forces. Anthracene is an interesting example in this category. Cruickshank (1956a) showed that... 

Bond orders and charge densities in the indigo molecule have been calculated [7] and compared with the results of X-ray analysis [8], These studies confirm the structural formula 1 and answer questions about the basic chromophore of the dye (see Section 2.4). 

Several studies on the supermolecular structure of aggregated intermacromolecular complexes performed by optical and electron microscopies have been reported. The obtained results are summarized in Table 26. Under polarized light, assemblies of intermacromolecular complexes appear to be light, as shown in Fig. 50. From the results of X-ray analysis and polarized... 

The higher boranes, also electron-deficient, clearly have hydrogen-bridge linkages. Structures, ascribed to them as the results of X-ray analysis, electron diffraction and microwave spectra, are available (Lipscomb, 1954). 

Much of our understanding of the secondary structure of proteins is the result of x-ray analysis. For many proteins the x-ray diffraction pattern indicates a regular repetition of certain structural units. For example, there are repeat distances of 7.0 A in silk fibroin, and of 1.5 A and 5.1 A in -keratin of unstretched wool. 

The mercury fulminate (MF) formula is HgCC N" —0 )2 with a covalent bond between the mercury and carbon atoms [20]. Its crystal density is reported to be 4.42-4.43 g cm [29, 30, 39, 40], but recent results of X-ray analysis updated it to 4,467 g cm [21]. Bulk density depends on crystal size and shape—it is reported to be between 1.35 and 1.55 g cm [38]. The heat of formation of MF is reported as being between —268 and —273 kJ moP [29, 41, 42]. The structure of the MF molecule and its crystal was published recently by Beck et al. [21]. Pure and ordinarily prepared mercury fulminate is, for all practical purposes, not hygroscopic, but its hygroscopicity rapidly increases in presence of impurities (e.g., mercury oxalate, calomel, mercuric chloride), which are generally present in the industrial... 

Figure 3-8 The results of X-ray analysis of Ag-Pd powder produced using various methods (simple mixing, copredpitation, solid solution alloy method).

Figure 8-14 The results of X-ray analysis of internal copper conductor (220) plane when measured from a variety of incidence angles.

Photodimerization of l- -octylthymine in a single crystal obtained from ethyl acetate was very fast and gave only one photodimer. The crystal structure determined by the results of x-ray analysis suggested this to be the trans-syn photodimer. However, the photodimer was identified as the trans-anti isomer from the NMR spectrum. 

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