Graphite, intercalation compounds lamellar

Graphite possesses the remarkable properly of forming many intercalation (lamellar or graphitic) compounds, the formation of which involves movement apart of the carbon layers and the penetration of atoms or ions between them. There are two general types of graphite intercalation compound in which the graphite layers remain planar ... 

In this technique, first, graphite intercalation compound (GIC) is prepared by the reaction of graphite with an intercalating agent. GIC is a unique class of lamellar materials formed by the intercalation of atomic or molecular guests in the interlayer... 

There is Htde evidence of the direct formation of sodium carbide from the elements (29,30), but sodium and graphite form lamellar intercalation compounds (16,31—33). At 500—700°C, sodium and sodium carbonate produce the carbide, Na2C2 above 700°C, free carbon is also formed (34). Sodium reacts with carbon monoxide to give sodium carbide (34), and with acetylene to give sodium acetyHde, NaHC2, and sodium carbide (disodium acetyHde), Na2C2 (see Carbides) (8). 

Molecules and ions can penetrate between the layers of graphite to form interstitial or lamellar compounds. These so-called intercalation compounds are of two types, namely, nonconducting compounds, in which the planarity of the graphite layers is destroyed, and conducting compounds, in which the planarity of the graphite layers is preserved (see Intercalation Chemistry) ... 

Intercalation constitutes an important case of inclusion phenomena in which the host lattice is characterized by a lamellar structure [39]. Graphite yields both anion and cation intercalation compounds and charge transfer processes are the driving forces for their formation. 

The formation of the non-conducting lamellar intercalation compounds graphite oxide and graphite fluoride - has been the subject of several... 

Intercalation compound A type of compound in which atoms, ions, or molecules are trapped between layers in a crystal lattice. There is no formal chemical bonding between the host crystal and the trapped molecules (see also clathrate). Such compounds are formed by lamellar solids and are often nonstoichiometric examples are graphitic oxide (graphite-oxygen) and the mineral muscovite. 

Intercalation of carbon fibers The crystal structure of graphite is of a kind that permits the formation of many compounds, called lamellar or intercalation compounds, by insertion of molecules or ions between the graphitic layers. 

Graphite reacts readily with the alkali metals potassium, calcium, strontium, and barium. The atoms of some of these metals, notably potassium, can readily penetrate between the basal planes of the graphite crystal to form intercalated (or lamellar compounds) with useful properties. These compounds are reviewed in Ch. 10, Sec. 3.0. 

Graphite reacts with tdkali metals to give lamellar compounds in which alkali metals are present in the form of monolayers separated by one or more carbon layers. The basicities measured by benzoic acid titration are shown in Fig. 3.3. The strongest basic sites are H = 18 both for potassium and cesium intercalated compounds. 

Beguin F, Setton R, Hamwi A (1979), The reversible intercalation of tetrahydrofuran in some graphite-alkah metal lamellar compounds . Mater Sci Eng, 40, 167-173. 

The reversible intercalation of various oxoacids under oxidizing conditions leads to lamellar graphite salts some of which have been known for over a century and are now particularly well characterized structurally. For example, the formation of the blue, first-stage compound with cone H2SO4 can be expressed by the idealized equation... 

It is well known that graphite and fluorine gas do not interact at room temperature and ordinary pressures. At higher temperatures (380-600 °C), the lamellar compounds (CjF) and (CF) are formed, in which the carbon atoms are disposed in puckered sheets (Riidorff Riidorff 1947a Kita et al. 1979). In the presence of HF, graphite is spontaneously intercalated by fluorine, at room temperature. The first accounts (Riidorff Riidorff of such a... 

Once graphite is formed, then it may react with a large number of substances to give lamellar compounds in which the reactant is present in the form of monolayers separated by one or more carbon layers.These compounds have been found to be active catalysts for various reactions in which the catalytic activity should not be described in terms of the reactant supported on graphite but, rather, in terms of formation of a new composite material. These intercalate catalysts will be considered below, but it should be stressed that they differ from a combination of alkali and carbon black (say), where the reactant is physically held in the pores of the carbon and acts as a supported catalyst. 

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