Buckminster fullerene, structure

The discovery of perfect geodesic dome closed structures of carbon, such as C o has led to numerous studies of so-called Buckminster fullerene. Dislocations are important features of the structures of nested fullerenes also called onion skin, multilayered or Russian doll fullerenes. A recent theoretical study [118] shows that these defects serve to relieve large inherent strains in thick-walled nested fullerenes such that they can show faceted shapes. 

If you re a sports fan, you ve almost certainly seen this structure before. It is that of a soccer ball with a carbon atom at each vertex. Smalley and his colleagues could have named this allotropic form of carbon "carbosoccer" or "soc-cerene," but they didn t. Instead they called it "buckminster fullerene" after the architect R. Buckminster Fuller, whose geodesic domes vaguely resembled truncated soccer balls. 

In C60 fullerene-type carbon allotrope, there is only one structure in which all the pentagons are nonadjacent and this is icosohedral symmetry-I (Fig. 4.11). This structure is often referred to as backyball to reflect on its full name buckminster-fullerene (after Buckminster Fuller who popularized the geodesic dome as an architectural form). 

Geodesic domes were a favorite design element of the architect and philosopher R. Buckminster Fuller, for whom buckminster-fullerene was named because of its structural resemblance to Fuller s domes. 

It is not possible to give here a complete review of DMol applications, so only a non-systematic selection of applications is mentioned here. Applications to chemical reactions have been studied by Seminario, Grodzicki and Politzer [10]. Buckminster-fullerenes have been studied by various groups [11] including also nonlinear optical properties [8] and the geometrical structure of Cs4 [13]. Cluster model studies of surfaces with adsorbates are reported in [14-17]. Cluster models for point defects in solids, in particular spin density studies of interstitial muon can be found in [18,19]. Spin density studies of molecular magnetic materials are in ref [20]. Polymers have been studied by Ye et al [21]. 

Huckel theory was extended to cover various other systems, including those with heteroatoms, but it was not particularly successful and has largely been superseded by other semi-empirical methods. Nevertheless, for appropriate problems Huckel theory can be very useful. One example is the calculations of P W Fowler and colleagues, who studied the relationship between geometry and electronic structure for a range of buckminster-fullerenes (the parent molecule of which, C50, was discovered in 1985) [Fowler 1993] The fullerenes (or buckyballs ) are excellent candidates for Hiickel theory as they are composed of carbon and have extensive tt systems three examples are shown in Figure 2.22. 

One of the most elegant ring structures is shown above and is known as buckminster-fullerene. It consists solely of 60 carbon atoms in rings that curve back on themselves to form a football-shaped cage. Count the number of bonds at any junction and you will see they add up to four so no hydrogens need be added. This compound is Cgo- Note that you can t see all the atoms as some are behind the sphere. 

The most stable of the boron modifications is j -rhombohedral boron (Figure 4.8), which has a unit cell made out of boron icosahedra with each atom being connected to the top of a pentagonal pyramid. This part of the structure is similar to a buckyball (Buckminster-Fullerene or C q), but this boron ball is filled with a boron icosahedron. The unit cell is finished with a single boron atom and two B q units that are draped as three fivefold rings around a central boron atom. The total number of boron atoms per unit cell in this modification is 105. 

The reaction of the dimers (Fp>2, Fp 2 with isocyanides in the presence of a catalytic quantity of triethylborane to give a mono substituted product is proposed to go via a radical chain process.The photoelectron spectra of the n -acetylides CpFe(CO>2C=CR R = H, Bu and Ph have been analysed and show significant interaction of the ir-orbitals with the metal dx orbitals based on the splitting of metal-based ionization bands, shifts in Cp-based and acetylide based ionizations, changes in ionization cross sections (Hel/Hell) and the vibrational fine structure in the metal based ionizations. The 19e complex [CpFtffCsMee) has been used as an electron reservoir in the multiple electron reduction of Buckminster fullerene. ... 

The four thermodynamically stable forms of carbon are diamond, graphite, Cgo, Buckminster fullerene, and carbon nanotubes. It would be a challenge to extend the experience gained in CNT to nanotubes made of other material than carbon. It would also be interesting to form stable spherical structures in the nanoscale dimensions without agglomeration. At what scale would the quantum analysis for atoms be applicable when compared with the Newtonian mechanics used to describe macro... 

Fullerenes, Fullerides. Molecular structures of atoms arranged on the surface of a sphere or a cylinder, in hexagonal and pentagonal arrays, in configurations similar to R. Buckminster Fuller s geodesic domes. Nanometersized tubes are being developed based on cylindrical Fullerenes. 28 to 540 carbon atoms in such a spherical arrangement form the most symmetric possible molecules - Buckminster Fullerene or Buckyballs . 

In very recent work, Amovilli et al [9] have carried out Hartree-Fock calculations on four almost-spherical C cages. Only for one of these cages, namely buckminster fullerene, is the structure of the lowest isomer known (European football). For the other three cages, namely Cso, C70 and Cg4, the lowest isomers are still not known. For Csa therefore, the classification of isomers by Mandopoulos and Fowler [36] has been utilized. The one chosen (albeit with inevitable arbitrariness) is that of the highest symmetry [Fig. 1(a) of Amovilli et al [9]]. For C70 similar symmetry considerations led them to a definite nuclear structure [Fig. 1(b) of Ref. [9]]. The framework adopted for C50 [see also Schmalz et al [37]] is given in Fig. 1(c) of Ref. [9]. 

As shown by the molecular structure of the compound C6o(Os04)-(4-tert-butylpyridine)2 reproduced in Fig. 4.49, the fulleride part of the molecule actually corresponds to a soccerball-like arrangement of carbon atoms. There, 20 six-member rings are fused with 12 five-member rings to give a carbon cluster with 32 faces. These features totally agree with the structure of the buckminster-fullerene discussed above. 

Two other forms of carbon have been discovered more recently. In the form called Buckminsterfullerene, or buckyball (named after R. Buckminster Fuller, who popularized the geodesic dome), 60 carbon atoms are arranged as rings of 5 and 6 atoms to give a spherical cage-Uke structure. When a fullerene structure is stretched out, it produces a cylinder with a diameter of only a few nanometers, called a nanotube. Practical uses for buckybaUs and nanotubes have not yet been developed, but it is hopeful that they can be used in lightweight structural materials, heat conductors, computer parts, and medicine. 

Carbon 60 (C60, Buckyball) is this third form of carbon, discovered in 1985 by Richard Smalley, Harold Kroto, and Robert Curl for which they won the 1996 Nobel Prize in chemistry. It is named as Buckministerfuller to honor the architect of the geodesic dome, Buckminster Puller, because the dome s shell resembles the fullerenes hollow-core construction. Fullerene structure of carbon is face-centered cubic having carbon molecules at the corners and at the center of the faces and belonging to the fullerene family. In the world of symmetry it is definitely a new form of pattern created by the existing symmetry operations. 

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

Bucky balls (football molecules) were only discovered in 1985 and named fullerene after the architect Buckminster-Fuller. The Nobel Prize for chemistry in 1996 was awarded for this new carbon chemistry. Molecular tubes with this structure have particularly interesting properties. 

Figure 4.19C shows Ceo, which is one type of fullerene discovered in 1985. It was given the name buckminsterfullerene because it resembles the geodesic-domed structure designed by architect R. Buckminster Fuller. Also known as buckyballs, Ceo is just one of several fullerenes that have been discovered. Others have been shown to have the formula C70, C74, and C82. Because of their spherical shape, researchers have speculated that fullerenes might make good lubricants. 

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