Carbon fullerenes and

Carbon is likely to congeal to high-molecular-weight polymers as H2 distills off. In extraterrestrial environments, we expect lower hydrocarbons eventually to transform into pure carbon, either diamond (in which all the carbons are singly bonded to other carbons), fullerenes and graphite (in which each interaction between a pair of carbons is the approximate equivalent of 1.5 bonds), or carbon bonded to other elements that cannot be converted to a volatile form. 

Recent work has indicated that Ni complexes can interact with buckminsterfullerene, Ceo, and related fiillerenes (see Carbon Fullerenes and Section 5.2). 

MWNT can also be prepared by laser ablation. Contrary to the synthesis of single-walled nanotubes, no catalyst is added here, but a pure graphite target is vaporized by means of a focused laser beam. The resulting MWNT are precipitated at cooler positions within the reactor. Here as well, the operating temperature is about 1200 °C because the number of defects increases and the yields of MWNT decrease at lower temperatures. Below 200 °C then, no growth of carbon nanotubes is observed anymore. The process produces a considerable portion of amorphous carbon, fullerenes, and carbon nanoparticles besides the desired MWNT. These impurities have to be removed before further use. The yields of multiwalled nanotubes usually range about 40%. 

Carbon nanotubes prepared by several methods are mixed with nanoparticles, amorphous carbon, fullerenes, and other contaminants [1576]. Nanotubes isolated from the mixture contain single-walled (SWNT) as well as multiwalled (MWNT) nanotubes. In general, the diameter of a SWNT is on the order of several nanometers, but the length can be several microns. Thus far, spectroscopic (mainly Raman) studies have been focused on SWNTs of small diameters (<2nm) that become metallic or semiconducting depending on their diameter and chirality. Chemical and physical... 

On an atomic scale, the majority of carbons exhibit the allotropic form of graphite, i.e. a sp -based structure, while diamond-like carbons, fullerenes and their derivatives, such as nanotubes, represent a shorter variety of carbon forms. However, depending on the degree of... 

Kolari, P.J., Maaranen, P., Kauppinen, E., Joutsensaari, J., Jauhiainen, K., Pelkonen, K., and Rannikko, S., Nanoparticles in biomedical apphcations experiments with activated carbon, fullerene and ferrous oxide, Med. Biol. Eng. Corrput., 34 (1), 153-154, 1996. 

Carbon nanotori spontaneously self assemble, in the same type of experiments, which lead to carbon fUllerenes and nanotubes. We have shown a generalization of the Descartes-Euler formula, called the Euler-Poincare... 

Some modifiers typically used for CNT functionalizing are listed in Table 25.1. It should be noted that the approaches used for CNT functioning are similar to those used for modification of polymer, activated carbon, fullerenes, and graphene surfaces. 

Metal-carbide clusters are relevant to the fonnation of both endohedral fullerenes and carbon nanotubes [1351. There also exists a class of apparently stable metal-carbide cluster ions, = Ti, V, Cr, Zr and Hf), called... 

The scope of tire following article is to survey the physical and chemical properties of tire tliird modification of carbon, namely [60]fullerene and its higher analogues. The entluisiasm tliat was triggered by tliese spherical carbon allotropes resulted in an epidemic-like number of publications in tire early to mid-1990s. In more recent years tire field of fullerene chemistry is, however, dominated by tire organic functionalization of tire highly reactive fullerene... 

An alternative approach envisages the stimulating idea to produce an all-carbon fullerene polymer in which adjacent fullerenes are linked by covalent bonds and align in well characterized one-, two- and tliree-dimensional arrays. Polymerization of [60]fullerene, with the selective fonnation of covalent bonds, occurs upon treatment under pressure and relatively high temperatures, or upon photopolymerization in the absence of a triplet quencher,... 

Prassides K, Kroto FI W, Taylor R, Walton D R M, David W I F, Tomkinson J, Fladdon R C, Rosseinsky M J and Murphy D W 1992 Fullerenes and fullerites in the solid state neutron soattering studies Carbon 8 1277-86... 

I he results of their calculations were summarised in two rules. The first rule states that at least one isomer C with a properly closed p shell (i.e. bonding HOMO, antibonding I. U.MO) exists for all n = 60 - - 6k (k = 0,2,3,..., but not 1). Thus Qg, C72, Cyg, etc., are in lhi-< group. The second rule is for carbon cylinders and states that a closed-shell structure is lound for n = 2p(7 - - 3fc) (for all k). C70 is the parent of this family. The calculations Were extended to cover different types of structure and fullerenes doped with metals. 

Buckminsterfullerene (Chapter 11 essay Carbon Clusters Fullerenes and Nanotubes ) Name given to the Cgo cluster with structure resembling the geodesic domes of R Buck minster Fuller see front cover... 

Benzene Dreams and Creative Thinking Carbon Clusters Fullerenes and Nanotubes... 

Fullerenes are a range of stable closed-shell carbon molecules and their derivatives, of which Qo is the archetype. The next highest stable member of the series is C70 which is found in small quantities with in arc electrode soot. C,o may be regarded as a Qo molecule with an extra belt of hexagons inserted at the... 

There are many applications for diamonds and related materials, e.g., diamondlike carbon films, and there are potential applications for Fullerenes and carbon nanotubes that have not yet been realised. However, the great majority of engineering carbons, including most of those described in this book, have graphitic microstructures or disordered graphitic microstructures. Also, most engineering carbon materials are derived firom organic precursors by heat-treatment in inert atmospheres (carbonisation). A selection of technically-... 

Drcssclhaus, M.S., Dresselhaus, G. and Eklund, P.C., Science of Fullerenes and Carbon Nanotubes, 1996, Academic Press, San Diego. 

As further research on fullerenes and carbon nanotubes materials is carried out, it is expected, because of the extreme properties exhibited by these carbon-based materials, that other interesting physics and chemistry will be discovered, and that promising applications will be found for fullerenes, carbon nanotubes and related materials. 

T. Ebbesen. In Fullerenes and Nanotuhes, edited by Pierre Delhaes and P. M. ykjayan, Gordon and Breach, Paris, France, 1998. Series World of Carbon, volume 2. 

Chapter 1 contains a review of carbon materials, and emphasizes the stmeture and chemical bonding in the various forms of carbon, including the foui" allotropes diamond, graphite, carbynes, and the fullerenes. In addition, amorphous carbon and diamond fihns, carbon nanoparticles, and engineered carbons are discussed. The most recently discovered allotrope of carbon, i.e., the fullerenes, along with carbon nanotubes, are more fully discussed in Chapter 2, where their structure-property relations are reviewed in the context of advanced technologies for carbon based materials. The synthesis, structure, and properties of the fullerenes and... 

---