Fullerene, its production, properties and applications.
Fullerene is a molecular compound belonging to the class of allotropic forms of carbon, and which is a convex closed polyhedron composed of an even number tricoordinated carbon atoms. The unique structure of fullerenes makes them unique physical and chemical properties.
Fullerene, baibala, or buckyballs — molecular compound belonging to the class of allotropic forms of carbon and which is a convex closed polyhedron composed of an even number tricoordinated atoms of carbon.
Fullerenes are named so by name of the engineer and architect Richard Buckminster fuller who designed and built a spatial structure “geodesic dome”, which is a hemisphere, assembled from tetrahedra. This design brought to fuller international recognition and acclaim. Today, its developments are being designed and built dome houses. Fullerene on the structure and shape of these structures by Richard Buckminster fuller.
The unique structure of fullerenes makes them unique physical and chemical properties. In connection with other substances they allow to obtain materials with radically new properties.
In the molecules of fullerenes, the atoms of carbon located at the vertices of hexagons and pentagons that form the surface of the sphere or ellipsoid. The most symmetrical and the most thoroughly studied representative of the family of fullerenes — fullerene (C60) in which the carbon atoms form a truncated icosahedron consisting of 20 hexagons and 12 pentagons and resembles a soccer ball (as the perfect form, rarely found in nature).
The next most common fullerene is C70, fullerene C60 is different from the insertion zone of the 10 atoms of carbon in the Equatorial region of C60, resulting in a fullerene C60 molecule is elongated and shaped like the ball for game in Rugby.
The so-called higher fullerenes containing more atoms of carbon (up to 400 or more), are formed in much smaller quantities and often have quite complex isomeric composition. Among the most studied higher fullerenes it is possible to allocate Cn, where n = 74, 76, 78, 80, 82 84.
The relationship between vertices, edges and faces of the fullerenes can be expressed by a mathematical formula according to Euler’s theorem for polyhedra:
B – R + G = 2,
where is the number of vertices of a convex polyhedron P is the number of its edges and G is the number of faces.
A necessary condition for the existence of a convex polyhedron according to the Euler’s theorem (and therefore of the existence of fullerenes with a certain structure and form) is the presence of exactly 12 pentagonal faces and/2 – 10 faces.
The possibility of the existence of buckyballs was predicted by Japanese scientists in 1971, the theoretical justification was made by Soviet scientists in 1973. The first fullerene was synthesized in 1985 in the United States.
Almost all fullerene prepared artificially. In nature it is found in very small quantities. It is formed during the combustion of natural gas and lightning, but is also found in very small quantities in shungites, the thunderbolts, meteorites and sediments, whose age is 65 million years.
Fullerene is easy to come into connection with other chemical elements. Currently, on the basis of fullerenes is synthesized over 3 million new and derived compounds.
If the composition of the fullerene molecule, in addition to carbon atoms include the atoms of other chemical elements, if the atoms of other chemical elements located within the carbon skeleton of such fullerenes are called endohedrally if outside Antakalnis.
– the materials as fullerenes have high strength, wear resistance, thermo – and chemostability and reduced abrasion,
– mechanical properties of fullerenes allow you to use them as highly effective antifrictional solid lubricant. On the surfaces of counterbodies, they form a protective fullerene polymer film thickness of tens to hundreds of nanometers, which protects against thermal and oxidative degradation, prolong the life time of friction in emergency situations in 3-8 times increases the thermal stability of the lubricants to 400-500 °C and the bearing capacity of friction in 2-3 times, extends the operating range of the friction pressures of 1.5-2 times, reduces the running time counterbodies,
fullerene is able to polymerize and form a thin film,
– a sharp decrease in transparency of a solution of fullerenes in excess of the intensity of optical radiation of a certain critical value due to nonlinear optical properties,
– the possibility of using fullerenes as the basis for a nonlinear optical gate, used to protect optical devices from intense optical radiation,
– fullerenes have the ability to show the properties of an antioxidant or oxidant. As antioxidants they are superior to all known antioxidants in 100 – 1000 times. Experiments were conducted on rats that were fed fullerenes in olive oil. Thus, the rats lived twice as long as usual, and, moreover, showed increased resistance to the action of toxic factors
is a semiconductor with a band gap of ~1.5 eV and its properties are similar to properties of other semiconductors,
fullerene C60, acting as a ligand interacting with the alkali and some other metals. In this form the complex compounds of the composition Ме3С60 having the properties of superconductors.
|Name of the parameter:||Value:|
|The thickness of the spherical shell nm||0,1|
|The radius of the molecule, nm||0,357|
|The bond length C-C between the atoms of carbon, nm|
|– the Pentagon||0,143|
|– in the hexagon||0,139|
* with regard to fullerene C60.
The main methods of producing fullerenes are considered to be:
– burning of graphite electrodes in electric arc in an atmosphere of helium at low pressure
– the burning of hydrocarbons in the flame.
It should be noted that a particular challenge is not only in itself, the obtaining of fullerenes (their output in the form of carbon black is extremely low), but followed by the extraction, purification and separation of fullerenes by classes of carbon black.
– anti-static, anti-wear and anti-friction polymers, plastics,
– sorbents for the food industry and water treatment,
– medications and pharmaceuticals,
as additives for synthetic diamond by high-pressure method. The output of diamonds increased by 30%,
– and much more.