Group intercalation compounds

The graphite-metal halides constitute the most populous group of intercalation compounds. Most of the investigative efforts have been directed towards the metal chlorides, particularly FeCls, whereas considerably less is known about the metal bromides S21). Compounds... 

X-Ray studies confirm that platinum crystallites exist on carbon supports at least down to a metal content of about 0.03% (2). On the other hand, it has been claimed that nickel crystallites do not exist in nickel/carbon catalysts (50). This requires verification, but it does draw attention to the fact that carbon is not inert toward many metals which can form carbides or intercalation compounds with graphite. In general, it is only with the noble group VIII metals that one can feel reasonably confident that a substantial amount of the metal will be retained on the carbon surface in its elemental form. Judging from Moss s (35) electron micrographs of a reduced 5% platinum charcoal catalyst, the platinum crystallites appear to be at least as finely dispersed on charcoal as on silica or alumina, or possibly more so, but both platinum and palladium (51) supported on carbon appear to be very sensitive to sintering. 

Elastic-inelastic collision model, Szilard-Chalmers reaction and, 1 269 Electrical conduction, in organic superconductors, 29 278-286 Electrical conductivity of chalcogenide halide compounds, 23 331 of Group IB, 23 337-339, 342, 346-349 photoelectric effects, 23 368, 410 semiconductors, 23 368, 390, 395-396, 400-402, 410-412 superconductors, 23 375-377 of graphite intercalation compounds, 23 290, 294, 309-310, 312, 317-318 Electric discharges arc type, 6 146-147 chemical reactions in, 6 189-191 chemical reactions in, 6 143-206... 

Omloo and Jellinek7 have described the synthesis and characterization of intercalation compounds of alkali metals with the group V layered transition metal dichalcogenides. Typically, these types of intercalation complexes are sensitive to moisture and must be handled in dry argon or nitrogen atmospheres. The alkali metal atoms occupy either octahedral or trigonal prismatic holes between X-M—X slabs. There are two principal means by which these compounds may be prepared. 

The dichalcogenides of group VI do not readily form intercalates with organic molecules. But n-alkylammonium compounds can be prepared by ion-exchange reactions of the hydrated sodium intercalation compounds such as Na j(H20)o g M0S2. Alkylammonium compounds prepared by this route show lattice expansions that depend on the alkyl chain length, very similar to the MX2-n-alkylamine systems described above. This raises the fundamental question whether protonated amines are the actual intercalated species in both the cases, involving reduction of the host. In fact, this constitutes the basis of the new model for the intercalation reaction in MX2 proposed by Schollhorn (1980). 

Liquid SbFj, with F2(j, was the only group 5 pentafluor-ide/Fj combination with fi-BN that brought about intercalation. Because there was always some fluorination of the /t-BN (to generate BF3) and there was never complete intercalation, the composition of the intercalation compound is not known. Since F2 was needed for intercalation, however, we can be sure that anion formation (SbFs) F is essential to the intercalation process. The interlayer spacing of 8.01 A is similar to that produced by the intercalation of hexafluoride species into graphite in a nonnestled way (30). 

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