Electron diffractograms

Electron microscopy has been performed using a sample synthesised at w = 10, [Cd2+]/[S2 ] = 2, and characterized by 430-nm absorption onset, which corresponds to a CdS diameter equal to 25 A. The microanalysis study shows the characteristic lines of sulfide and cadmium ions, indicating that the observed particles are CdS semiconductor crystallites. The electron diffractogram shows concentric circles, which are compared to a simulated diffractogram of bulk CdS. A good agreement between the two spectra is obtained, indicating the particles keep zinc-blend crystalline structure (fee) with a lattice constant equal to 5.83 A. 

Figure 6.8 (a) SEM image, (b) electron diffractogram and (c) C7Stal packing structure of [Ni(tacn)2]2[a-SiWn204o] [133]. 

The d-values of the electron diffractogram allowed us to fully index the X-ray fiber diagram using a triclinic unit cell. Without the electron diffraction reciprocal cell parameters (a, b, Y ) the task of indexing the fiber diagram would have been more difficult because of the paucity of hkO reflections on the equator. 

When nitrobenzene alone is used as a solvent (170 C) and with slow cooling, lamellar single crystals are obtained. Their electron diffractograms have an oblique cell (plane group p2). With a mixture of nitrobenzene/decane (65/35) or nitrobenzene/ hexane the dissolution temperature is reduced to about 70 C. 

Figure 1. 6GT single crystals and corresponding electron diffractograms. (top) Single crystals with an oblique cell (bottom) single crystals with a rectangular cell. 

The electron diffractogram in Fig. 4 shows the expected symmetry based on the known unit cell dimensions. The systematic absences for the P2j2i2i space group were noted and some 42 separate reflections could be observed which provided 16 distinct baseplane reflections. These were used to compare the... 

Figure 4. Single crystal of poly(t-caprolactone) and its electron diffractogram...

Figure 4. Electron micrograph and electron diffractogram of fresh catalysts.

Fig. 14.—Polymer Single Crystal from Esparto-grass Xylan. (Screw dislocations and lamellar texture are typical of these crystals, which contain folded polymer-chains. The insert shows the schematic diagram of the electron diffractogram that corresponds to the dry crystal form (see Section V,l, p. 460), and confirms that the molecular axis is normal to the lamellar plane).

Figure 5. TEM micrographs and an electron diffractogram of TMT film prepared with an oxygen flow rate of 1.5 X 10 cm S 1 (STP) (Position of the deposited films from the monomer inlet port in the reactor for a, b and d = 24 cms and c = 65 cms). (a) TMT metallic film, (b) TMT...

The HREM study showed some additional features of the packing of the Pd atoms. " "" Although some cluster metal particles have a five-fold axis typical of an icosahedron (Fig. 2a), the more abundant metal particles seemed from the micrographs to be arranged according to face-centered cubic (f.c.c.) packing (Fig. 2b), and this was confirmed by the electron diffractograms for the same cluster samples. 

Fig. 2. Chitin usually occurs in the form of microfibrils in many organisms. Shown here are /S-chitin microfibrils from Tevnia jerichonana, a deep sea hydrothermal vent worm. The insert is a typical electron diffractogram oriented with respect to the bundle. The image was obtained by transmission electron microscopy (TEM) after protein removal (22). Reproduced with permission.

The relation between conductivity, chemical and phase compositions, and the structure of separate phases of solid electrolytes is very important In many systems, the maximum in conductivity closely coincides with the existing F-phase (fluorite-phase) limit TEM image of Figure 13.3 shows the formation of a dense single-phase polycrystalline microstructure for the sintered ceramics [1]. X-ray diffraction and analysis of electron diffractograms of this sintered ceramic confirmed the fluorite structure. 

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