Fullerene solids

The structure-property relations of fullerenes, fullerene-derived solids, and carbon nanotubes are reviewed in the context of advanced technologies for carbon-hased materials. The synthesis, structure and electronic properties of fullerene solids are then considered, and modifications to their structure and properties through doping with various charge transfer agents are reviewed. Brief comments are included on potential applications of this unique family of new materials. 

Since the structure and properties of fullerene solids are strongly dependent on the structure and properties of the constituent fullerene molecules, we first review the structure of the molecules, which is followed by a review of the structure of the molecular solids formed from Ceo, C70 and higher mass fullerenes, and finally the structure of Cgo crystals. 

Assink et al [ 1 ] have pointed out that fullerenes may provide an efficient way for gas storage. Usually gas C60 interstitial compounds are produced by hot pressing the fullerene solid (fullerite) at temperatures between 200 - 550°C and under gas pressures in the range 170-200 MPa for set periods from 12 to 60h. With this method Ar, Kr and Xe[2] as well as CO [3], C02 [4] and N20 [5] fullerene compounds were produced. 

The reactivity of the molecular fullerene solid resembles the expected pattern for a homogeneous material. Only a small prereactivity at 700 K indicates that a fullcrcne-oxygen complex [12] is formed as an intermediate stoichiometric compound [15, 105], At 723 K the formation of this compound and the complete oxidation are in a steady state [12, 106, 107] with the consequence of a stable rate of oxidation which is nearly independent of the bum-off of the fullerene solid. This solid transforms prior to oxidation into a disordered polymeric material. The process is an example of the alternative reaction scenario sketched above for the graphite oxidation reaction. The simultaneous oxidation of many individual fullerene molecules. leaving behind open cages with radical centers, is the reason for the polymerization. 

Keywords CP/MAS Host-guest chemistry Molecular motion Calixarenes Cyclodextrins Cyclophosphazenes Fullerenes Solid-state NMR... 

Soon after the discovery of methods for the mass production of fuUerenes, the pyrolysis and gasification behavior of these novel carbons attracted considerable interest due to unexpected findings regarding traditional carbons [11, 12]. In this context, Ismail and Rodgers [11] reported some of the first results on adsorption on fullerene solids. Batches of C50 of different origin were studied. 

Mizoguchi, K., Magnetic resonance of fullerene solids and their compounds, J. Phys. Chem. Solids, 54, 1693, 1993. 

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