Prediction – предсказывание
Beam – луг
Discrete – отдаленный
Obtain – получать
Occurrence – появление
Soot – копоть; сажа
Residue – остаток
Lightning discharge – разряд молнии
Interstellar dust – космическая пыль
Current- ток
Purification- чистота; очистка
Layer- слой
Reduce- уменьшать
Property – свойство
Resistance – сопротивление
Develop – развивать
Science fiction – фантастика
Armor – доспех
Describe – описывать
Fullerenes are a family of (other allotropes of carbon are graphite and diamond) consisting of composed entirely of carbon atoms arranged in the form of hollow , ellipsoids, or tubes. Each molecule generally has both pentagonal and hexagonal faces.
The most common fullerene is Buckminsterfullerene, in which each molecule is composed of 60 carbon atoms that together take the shape of a ball. It was named after , because its shape resembles Fuller's design of a geodesic dome. By extension, sph erical fullerenes are often called buckyballs, and cylindrical ones are called buckytubes, or, more accurately, . Fullerenes are similar in structure to , which is composed of stacked sheets of linked hexagonal rings. In the case of a fullerene, however, the presence of pentagonal (or sometimes heptagonal) rings prevents its sheets from being planar.
Chemists can now produce various derivatives of fullerenes. For example, hydrogen atoms, halogen atoms, or organic can be attached to fullerene molecules. Also, ions, atoms, or small molecules can be trapped in the cage-like structures of fullerene molecules, producing complexes that are known as endohedral fullerenes. If one or more carbon atoms in a fullerene molecule is replaced by metal atoms, the resultant compound is called a fulleride. Some doped fullerenes (doped with or atoms, for example) are at relatively high temperatures
Coining the name
Buckminsterfullerene (C60) was named after , a noted architectural modeler who popularized the geodesic dome. Since buckminsterfullerenes have a similar shape to that sort of dome, the name was thought to be appropriate. As the discovery of the fullerene family came after buckminsterfullerene, the shortened name "fullerene" was used to refer to the family of fullerenes.
Prediction and discovery
In 1970, Eiji Osawa of Toyohashi University of Technology predicted the existence of C60 molecules. He noticed that the structure of a corannulene molecule was a subset of a soccer-ball shape, and he made the hypothesis that a full ball shape could also exist. His idea was reported in Japanese magazines, but did not reach Europe or America.
In molecular beam experiments, discrete peaks were observed corresponding to molecules with the exact masses of 60, 70, or more of carbon atoms. In 1985, Harold Kroto (then at the University of Sussex), James R. Heath, Sean O'Brien, Robert Curl, and Richard Smalley, of Rice University, discovered C60, and shortly thereafter discovered other fullerenes. The first nanotubes were obtained in 1991.
Kroto, Curl, and Smalley were awarded the 1996 for their roles in the discovery of this class of compounds.
Natural occurrence and artificial production
Minute quantities of the fullerenes – in the form of C60, C70, C76, and C84 molecules – have been found in soot and in the residue of carbon arc lamps. These molecules are also produced by lightning discharges in the atmosphere. Some analyses indicate that they are present in meteorites and interstellar dust. Recently, Buckminsterfullerenes were found in a family of minerals known as Shungites in Karelia, Russia.
A common method used to produce fullerenes is to send a large current between two nearby electrodes in an inert atmosphere. The resultant arc between the electrodes cools into sooty residue from which many fullerenes can be isolated.
By 1991, it became relatively easy to produce gram-sized samples of fullerene powder using the techniques of Donald Huffman and Wolfgang Krätschmer. However, purification of fullerenes remains a challenge.
Structural variations
Since the discovery of fullerenes in 1985, a number of structural variations of fullerenes have been found. Examples include:
• buckyball clusters: The smallest member is C 20 (unsaturated version of dodecahedrane) and the most common is C 60
• Nanotubes: Hollow tubes of very small dimensions, having single or multiple walls; potential applications in electronics industry
• Megatubes: Larger in diameter than nanotubes and prepared with walls of different thickness; potentially used for the transport of a variety of molecules of different sizes
• Polymers: Chain, two-dimensional and three-dimensional polymers are formed under high pressure high temperature conditions
• Nano onions: Spherical particles based on multiple carbon layers surrounding a buckyball core; proposed for lubricant
• Fullerene rings
Buckyballs Buckminsterfullerene C60
A soccer ball is a model of the Buckminsterfullerene C60
Carbon nanotubes
Nanotubes are cylindrical fullerenes. These tubes of carbon are usually only a few nanometers wide, but they can range from less than a micrometer to several millimeters in length. They often have closed ends, but can be open-ended as well. There are also cases in which the tube reduces in diameter before closing off. Their unique molecular structure results in extraordinary macroscopic properties, including high tensile strength, high electrical conductivity, high ductility, high resistance to heat, and relative chemical inactivity (as it is cylindrical and "planar" – that is, it has no "exposed" atoms that can be easily displaced). One proposed use of carbon nanotubes is in paper batteries, developed in 2007 by researchers at Rensselaer Polytechnic Institute. Another proposed