Fullerene, fullerite

Keywords C60 Fullerene Fullerite Fulleride C60 polymer Superconductivity Density functional theory... 

Non-Carbon and Layered Fullerenes. Fullerene-Like Clusters Fullerene Formation Mechanism FuUerene Molecules with Defects Solid Fullerene - Fullerite... 

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... 

Saito S, Umemoto K, Miyake T (2004) Electronic Structure and Energetics of Fullerites, Fullerides, and Fullerene Polymers 109 41-57 Sakata M, see TakataM (2004) 109 59-84... 

Fullerenes are the third natural form of carbon. These have been found to exist in interstellar dust and in geological formations on Earth, but only in 1985 did Smalley, Kroto and co-workers discovered this class of carbon solids and their unusual properties [447, 448]. It has been shown that Ceo, the most common fullerene, could be transformed under high pressure into the other forms of carbon, diamond, and graphite [449] or, at moderately high pressures and temperatures, into new various metastable forms [450 53]. Ceo crystals, fullerites, have/cc structure with weak van der Waals interactions. This structure is stable at ambient temperature up to 20 GPa and at ambient pressure up to 1800 K [454, 455]. 

Graphite and diamond are network solids that are insoluble in all liquid solvents except some liquid metals. Flowever, the fullerenes, which are molecular, can be dissolved by suitable solvents (such as benzene) buckminsterfullerene itself forms a red-brown solution. Fullerite currently has few uses, but some of the compounds of the fullerenes have great promise. For example, K3C60 is a superconductor below 18 K, and other compounds appear to be active against cancer and diseases such as AIDS. 

Direct catalyzed hydrogenation of crystalline fullerite or fullerenes in solution. 

Small carbon grains are assumed to be the carrier of the prominent interstellar ultra violet absorption at 217 nm. To investigate this hypothesis, we produced small carbon particles by evaporating graphite in an inert quenching gas atmosphere, collected the grains on substrates, and measured their optical spectra. In the course of this work - which in the decisive final phase was carried out with the help of K. Fostiropoulos and L. D. Lamb - we showed that the smoke samples contained substantial quantities of C60. The fullerene C60 (with small admixtures of C70) was successfully separated from the sooty particles and, for the first time, characterized as a solid. We suggested the name fullerite for this new form of crystalline carbon. 

Figure 14. Unit cells of fullerite with bcc (a) and fee (b) structures with lattice hydrogen only. (Shaded circle) Sites of crystalline lattices, in which fullerenes molecules are distributed ( ) octahedral (O) interstitial sites (o) tetrahedral...

The derived formula (38) determines the dependence of free energy of bcc fullerite on temperature, fullerene concentrations, hydrogen content, its activity, and energetic constants. 

We assume that the crystal lattice of fullerite in its ordered state is the one of the Ll0 type (Figure 16). In this lattice the sites of the first and the second types valid for and 2 fullerenes, respectively, alternate in layers. In this case O, 0, Q, D interstices, depending on their surrounding by the... 

In the ordered fullerite the /th configuration of 1 2 fullerenes is defined by the configuration of fullerenes in the lattice sites of the first and second type, respectively, i.e., the l value is determined by the sum l = i + j, where i is the number of i fullerenes in the lattice sites of the first type, and j is the number of the same i fullerenes in the lattice sites of the second type around each interstitial sites. 

Formulae (60) and (63) with regard to the relations (61) and (47) determine the corresponding hydrogen solubilities in dependence on the fullerite composition (ci, c2 concentrations), temperature, degree of the long-range order in the fullerenes distribution over the lattice sites, and the energetic constants. 

Hence the statistical and thermodynamical theory of the lattice hydrogen solubility in fee fullerite with consideration for the hydrogen atoms distribution over the interstitial sites of different types has allowed us to explain and justify the formation of HX hydrofullerites with high hydrogen concentration when 0 < x < 18. It has been found that hydrogen solubility depends on the fullerite composition, its temperature, the order parameter in i = C6o, 2 = C70 fullerenes distribution over the lattice sites, the energetic constants characterizing the interaction between H- pairs at the different distances. 

Electronic Structure and Energetics of Fullerites, Fullerides, and Fullerene Polymers... 

---