Carbon allotrope: buckminsterfullerene

There are many other fused systems, of which pyrene is a more complex example. An interesting system is the Cg carbon allotrope, buckminsterfullerene, which consists of 12 five- and 20 six-membered rings fused together to form the so-caiied buckyball". Many poiycyclic hydrocarbons are potent carcinogens. 

Haddon, R. C. Raghavachari, K. 1992 Electronic structure of the fullerenes carbon allotropes of intermediate hybridization, buckminsterfullerenes. VCH. (In the press.)... 

The third allotropic form of carbon is buckminsterfullerene, affectionately called the buckey ball. The buckey ball consists of sixty carbon atoms in the shape of a soccer ball. Discovered in the 1980s, buckminsterfullerene was named for Buckminster Fuller, who used such shapes in the design of geodesic domes. 

The three solid elemental forms of carbon (allotropes) diamond, graphite, and buckminsterfullerene. The representations of diamond and graphite are fragments of much larger structures that extend in all directions from the parts shown here. Buckminsterfullerene contains Cgo molecules, one of which is shown. 

Buckminsterfullerene is an allotrope of carbon in which the carbon atoms form spheres of 60 atoms each (see Section 14.16). In the pure compound the spheres pack in a cubic close-packed array, (a) The length of a side of the face-centered cubic cell formed by buckminsterfullerene is 142 pm. Use this information to calculate the radius of the buckminsterfullerene molecule treated as a hard sphere, (b) The compound K3C60 is a superconductor at low temperatures. In this compound the K+ ions lie in holes in the C60 face-centered cubic lattice. Considering the radius of the K+ ion and assuming that the radius of Q,0 is the same as for the Cft0 molecule, predict in what type of holes the K ions lie (tetrahedral, octahedral, or both) and indicate what percentage of those holes are filled. 

Buckminsterfullerene, an allotrope of carbon, is topologically equivalent to a truncated icosahedron, an Archimedean solid that possesses 12 pentagons and 20 hexagons (Fig. 9-16). [17] Each carbon atom of this fullerene corresponds to a vertex of the polyhedron. As a result, C6o is held together by 90 covalent bonds, the number of edges of the solid. 

The 1996 Nobel Prize in chemistry was awarded to three American scientists for their identification of a new allotrope of aromatic carbon molecules called fullerenes. These unusual carbon molecules form a closed-cage structure of joined carbon atoms. The original soccer ball-shaped carbon molecule called buckminsterfullerene contained 60 carbon atoms and was nicknamed Bucky Ball in honor of Buckminster Fuller (1859—1983), who used similar shapes in some of his architectural structures. Since then additional organic pentagon structures beyond the original icosahedral fullerene (C ) have been developed, all with an even... 

Another major center of research on carbon nanotubes has been the Center for Nanoscale Science and Technology at Rice University. The center s director from 1997 to his death in 2005 was Richard Smalley, who was awarded a share of the 1997 Nobel Prize in chemistry for his part in the discovery of a new allotrope of carbon. The discovery, a 60-atom soccer hall-shaped particle originally named buckminsterfullerene, is more commonly known as a buckyball. The structure of a buckyball is shown in the photograph on page 91. 

As stated by Smalley, the name [fullerene] was bom in the dimmest early thinking of how a pure carbon cluster of 60 atoms could eliminate its dangling bonds (Billups and Ciufolini, 1993, foreword vi). In an effort to make clear the shape of the cluster, Smalley asked Kroto the name of the architect who worked with big domes. The answer was Buckminister Fuller. Carbon clusters of all sizes were subsequently named Buckminsterfullerenes, fullerenes, or sometimes buckyballs. A third allotrope of carbon had thus been added to the two (graphite and diamond) already known (see Figure 1). 

In the mid-1980s, virtually simultaneous reports on two new precise molecular level constructions of sub-nanoscopic/nanoscopic size appeared in the literature. In 1984 we (DAT) reported the synthesis, isolation and characterization of the first iterated series of Starburst/cascade dendrimers based on genealogical synthesis [2, 77-83]. The following year Smalley, Curl and Kroto described the first observation of a 60-carbon fullerene by mass spectroscopy [43a]. More recently the synthesis of buckminsterfullerene has been achieved by physicists at the Max Planck Institute in Heidelberg [44] to give macroscopic quantities of the third allotropic and first molecular form of carbon, named after Buckminster Fuller. Similarities between these two constructions were not initially apparent, but in retrospect they deserve comment in so far as they each involve molecular level synthesis leading to closed geometrical architecture". 

We used to believe that there are three allotropic forms of carbon graphite, diamond, and amorphous carbon. However, an important new carbon al-lotrope, the fullerenes, was discovered as recently as the 1980s. The most famous fullerene is buckminsterfullerene, Ceo, which is depicted in Fig. 3.1. The structure of this soccer ball-shaped molecule consists of a sphere of sixty carbon atoms arranged in pentagons and hexagons each carbon pentagon is surrounded by five carbon hexagons. 

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