Graphitic giant

Pethica J B 1986 Comment on interatomic forces in scanning tunnelling microscopy giant corrugations of the graphite surface Phys. Rev. Lett. 57 3235... 

Boron nitride is chemically unreactive, and can be melted at 3000 K by heating under pressure. It is a covalent compound, but the lack of volatility is due to the formation of giant molecules as in graphite or diamond (p. 163). The bond B—N is isoelectronic with C—C. 

Pure carbon occurs naturally in two modifications, diamond and graphite. In both these forms the carbon atoms are linked by covalent bonds to give giant molecules (Figure S.2). 

The remarkable stability of onion-like particles[15] suggests that single-shell graphitic molecules (giant fullerenes) containing thousands of atoms are unstable and would collapse to form multi-layer particles in this way the system is stabilized by the energy gain from the van der Waals interaction between shells [15,26,27],... 

In covalent network solids, covalent bonds join atoms together in the crystal lattice, which is quite large. Graphite, diamond, and silicon dioxide (Si02) are examples of network solids. The crystal is one giant molecule. 

M. Terrones, G. Terrones, H. Terrones, Structure, chirality, and formation of giant icosahedral fullerenes and spherical graphitic onions, Struct. Chem., vol. 13, pp. 373-384, 2002. 

The raw product obtained by the evaporation of graphite is soot and slag. Next to soluble fullerenes the soot and slag contain other kinds of closed carbon structures, e.g. giant fullerenes [187] and nanotubes [188, 189] the rest is amorphous carbon. Fullerenes can be isolated from the soot either by sublimation or by extraction. The first isolation of fullerenes was achieved by a simple sublimation with a Bunsen... 

Figure 3.32a shows the structure of graphite. This is a layer structure. Within each layer each carbon atom is bonded to three others by strong covalent bonds. Each layer is therefore like a giant molecule. Between these layers there are weak forces of attraction (van der Waals forces) and so the layers will pass over each other easily. 

Fullerenes and graphite may originate abundantly in stellar atmospheres rich in carbon like those of some giant stars and some progenitors of planetary nebulae (Fig. 1.5). These objects display for important mass loss rates and are therefore able to greatly enrich the interstellar medium. 

Dreams in a charcoal fire predictions about giant fullerenes and graphite nanotubes... 

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