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Encyclopedia > Allotropes of carbon
Eight allotropes of carbon: a) Diamond, b) Graphite, c) Lonsdaleite, d) C60 (Buckminsterfullerene or buckyball), e) C540, f) C70, g) Amorphous carbon, and h) single-walled carbon nanotube or buckytube.
Eight allotropes of carbon: a) Diamond, b) Graphite, c) Lonsdaleite, d) C60 (Buckminsterfullerene or buckyball), e) C540, f) C70, g) Amorphous carbon, and h) single-walled carbon nanotube or buckytube.
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Nanomaterials · Fullerene
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Timeline · Carbon allotropes
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K. Eric Drexler
Engines of Creation

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This is a list of the allotropes of carbon. Image File history File links Question_book-3. ... Image File history File links Download high resolution version (1762x1895, 1517 KB) Summary This illustration depicts eight of the allotropes (different molecular configurations) that pure carbon can take: a) Diamond b) Graphite c) Lonsdaleite d) Buckminsterfullerene (C60) e) C540 f) C70 g) Amorphous carbon h) single-walled carbon nanotube Created... Image File history File links Download high resolution version (1762x1895, 1517 KB) Summary This illustration depicts eight of the allotropes (different molecular configurations) that pure carbon can take: a) Diamond b) Graphite c) Lonsdaleite d) Buckminsterfullerene (C60) e) C540 f) C70 g) Amorphous carbon h) single-walled carbon nanotube Created... For other uses, see Carbon (disambiguation). ... This article is about the mineral. ... For other uses, see Graphite (disambiguation). ... Lonsdaleite is a hexagonal allotrope of the carbon allotrope diamond, believed to form when meteoric graphite falls to Earth. ... Buckminsterfullerene (C60) Fullerenes are molecules composed entirely of carbon, taking the form of a hollow sphere, ellipsoid, or tube. ... Buckminsterfullerene (C60) Fullerenes are molecules composed entirely of carbon, taking the form of a hollow sphere, ellipsoid, or tube. ... Amorphous carbon is the name used for carbon that does not have any crystalline structure. ... 3D model of three types of single-walled carbon nanotubes. ... An electronic device known as a diode can be formed by joining two nanoscale carbon tubes with different electronic properties. ... Although nanotechnology is a relatively recent development in scientific research, the development of its central concepts happened over a longer period of time. ... Potential risks of nanotechnology can broadly be grouped into four areas: the risk of environmental damage from nanoparticles and nanomaterials the risk posed by molecular manufacturing (or advanced nanotechnology) societal risks health risks Nanoethics concerns the ethical and social issues associated with developments in nanotechnology, a science which encompass several... This article or section does not cite its references or sources. ... This is a list of organizations involved in nanotechnology. ... This is a list of references and appearances of Nanotechnology in works of fiction. ... This page aims to list all topics related to the field of nanotechnology. ... Nanomedicine is the medical application of nanotechnology. ... An example of a molecular self-assembly through hydrogen bonds reported by Meijer and coworkers in Angew. ... Molecular electronics (sometimes called moletronics) is a branch of applied physics which aims at using molecules as passive (e. ... Scanning probe microscopy (SPM) is a branch of microscopy that forms images of surfaces using a physical probe that scans the specimen. ... Nanolithography — or lithography at the nanometer scale — refers to the fabrication of nanometer-scale structures, meaning patterns with at least one lateral dimension between the size of an individual atom and approximately 100 nm. ... Molecular nanotechnology (MNT) is the concept of engineering functional mechanical systems at the molecular scale. ... Nanomaterials is the study of how materials behave when their dimensions are reduced to the nanoscale. ... The Icosahedral Fullerene C540 C60 and C-60 redirect here. ... 3D model of three types of single-walled carbon nanotubes. ... Nanotube membranes are films composed of open-ended nanotubes that are oriented perpendicularly to the surface of the film like the cells of a honeycomb. ... Fullerene chemistry is a field of organic chemistry devoted to the chemical properties of fullerenes [1] [2] [3]. Research in this field is driven by the need to functionalize fullerenes and tune their properties. ... Carbon nanotubes have many potential applications, here is a short list of some of the most important: // clothes: waterproof tear-resistant cloth fibers combat jackets: MIT is working on combat jackets that use carbon nanotubes as ultrastrong fibers and to monitor the condition of the wearer. ... Examples of fullerenes in popular culture are numerous. ... Timeline of carbon nanotubes: Inside a carbon nanotube 1952 Radushkevich and Lukyanovich publish a paper in the Russian Journal of Physical Chemistry showing hollow graphitic carbon fibers that are 50 nanometers in diameter. ... It has been suggested that nanopowder be merged into this article or section. ... A quantum dot is a semiconductor nanostructure that confines the motion of conduction band electrons, valence band holes, or excitons (bound pairs of conduction band electrons and valence band holes) in all three spatial directions. ... Colloidal gold is a suspension (or colloid) of sub-micrometre-sized particles of gold in a fluid, usually water. ... --210. ... A molecular assembler is a molecular machine capable of assembling other molecules given instructions, energy, and a supply of smaller building block molecules to work from. ... It has been suggested that this article or section be merged with mechanochemistry. ... Nanorobotics is the technology of creating machines or robots at or close to the scale of a nanometres (10-9 metres). ... Grey goo is a hypothetical end-of-the-world scenario involving molecular nanotechnology in which out-of-control self-replicating robots consume all living matter on Earth while building more of themselves (a scenario known as ecophagy). ... K. Eric Drexler in 2001. ... Engines of Creation: The Coming Era of Nanotechnology Engines of Creation (ISBN 0-385-19973-2) is a seminal molecular nanotechnology book written by K. Eric Drexler in 1986. ... Allotropy (Gr. ... For other uses, see Carbon (disambiguation). ...

Contents

Diamond

Main article: Diamond

Diamond is one of the best known allotropes of carbon, whose hardness and high dispersion of light make it useful for industrial applications and jewelry. Diamond is the hardest known natural mineral, which makes it an excellent abrasive and makes it hold polish and lustre extremely well. This article is about the mineral. ... Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure. ... For other uses, see Mineral (disambiguation). ...


The market for industrial-grade diamonds operates much differently from its gem-grade counterpart. Industrial diamonds are valued mostly for their hardness and heat conductivity, making many of the gemological characteristics of diamond, including clarity and color, mostly irrelevant. This helps explain why 80% of mined diamonds (equal to about 100 million carats or 20,000 kg annually), unsuitable for use as gemstones and known as bort, are destined for industrial use. In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately after their invention in the 1950s; another 400 million carats (80,000 kg) of synthetic diamonds are produced annually for industrial use—nearly four times the mass of natural diamonds mined over the same period. Gemology (gemmology outside the United States) is the science, art and profession of identifying and evaluating gemstones. ... Bort or boart is a term used in the diamond industry to refer to shards of gem-grade/quality diamonds. ...


The dominant industrial use of diamond is in cutting, drilling, grinding, and polishing. Most uses of diamonds in these technologies do not require large diamonds; in fact, most diamonds that are gem-quality can find an industrial use. Diamonds are embedded in drill tips or saw blades, or ground into a powder for use in grinding and polishing applications. Specialized applications include use in laboratories as containment for high pressure experiments (see diamond anvil), high-performance bearings, and limited use in specialized windows. A diamond anvil, more properly a diamond anvil cell (DAC), is a device used by physicists to exert extreme pressures on a material. ... A bearing is a device to permit constrained relative motion between two parts, typically rotation or linear movement. ... For other uses, see Window (disambiguation). ...


With the continuing advances being made in the production of synthetic diamond, future applications are beginning to become feasible. Garnering much excitement is the possible use of diamond as a semiconductor suitable to build microchips from, or the use of diamond as a heat sink in electronics. Significant research efforts in Japan, Europe, and the United States are under way to capitalize on the potential offered by diamond's unique material properties, combined with increased quality and quantity of supply starting to become available from synthetic diamond manufacturers. A semiconductor is a solid whose electrical conductivity is in between that of a conductor and that of an insulator, and can be controlled over a wide range, either permanently or dynamically. ... Integrated circuit of Atmel Diopsis 740 System on Chip showing memory blocks, logic and input/output pads around the periphery Microchips with a transparent window, showing the integrated circuit inside. ... CPU heat sink with fan attached A heat sink (or heatsink) is an environment or object that absorbs and dissipates heat from another object using thermal contact (either direct or radiant). ... This article is about the engineering discipline. ... For other uses, see Europe (disambiguation). ...


Each carbon atom in a diamond is covalently bonded to four other carbons in a tetrahedron. These tetrahedrons together form a 3-dimensional network of puckered six-membered rings of atoms. This stable network of covalent bonds and the three dimensional arrangement of bonds is the reason that diamond is so strong. Covalent bonding is a form of chemical bonding characterized by the sharing of one or more pairs of electrons between atoms, in order to produce a mutual attraction, which holds the resultant molecule together. ...


Graphite

Main article: Graphite

Graphite (named by Abraham Gottlob Werner in 1789, from the Greek γράφειν: "to draw/write", for its use in pencils) is one of the most common allotropes of carbon. Unlike diamond, graphite is a conductor, and can be used, for instance, as the material in the electrodes of an electrical arc lamp. Graphite holds the distinction of being the most stable form of solid carbon ever discovered. For other uses, see Graphite (disambiguation). ... Abraham Gottlob Werner Abraham Gottlob Werner (1749 or 1750 - 1817), was born in Wehrau, a city in Prussian Silesia, southeastern Germany. ... Year 1789 (MDCCLXXXIX) was a common year starting on Thursday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Monday of the 11-day slower Julian calendar). ...


Graphite is able to conduct electricity, due to delocalization of the pi bond electrons above and below the planes of the carbon molecules These electrons are free to move, so are able to conduct electricity. However, the electricity is only conducted along the plane of the layers. In diamond all four outer electrons of each carbon atom are 'localised' between the atoms in covalent bonding. The movement of electrons is restricted and diamond does not conduct an electric current. In graphite, each carbon atom uses only 3 of its 4 outer energy level electrons in covalently bonding to three other carbon atoms in a plane. Each carbon atom contributes one electron to a delocalised system of electrons that is also a part of the chemical bonding. The decolcalised electrons are free to move throughout the plane. For this reason, graphite conducts electricity along the planes of carbon atoms, but does not conduct in a direction at right angles to the plane. Look up conduct in Wiktionary, the free dictionary Conduct can be: A noun meaning behaviour (as in good conduct) A verb meaning to direct (usually an orchestra; see Category:Conductors) Conduction. ... Electricity (from New Latin Ä“lectricus, amberlike) is a general term for a variety of phenomena resulting from the presence and flow of electric charge. ... In chemistry, delocalized electrons are electrons in a molecule that do not belong to a single atom or a covalent bond. ... Electron atomic and molecular orbitals, showing a Pi-bond at the bottom right of the picture. ... Properties The electron (also called negatron, commonly represented as e−) is a subatomic particle. ...


Graphite powder is used as a dry lubricant. Although it might be thought that this industrially important property is due entirely to the loose interlamellar coupling between sheets in the structure, in fact in a vacuum environment (such as in technologies for use in space), graphite was found to be a very poor lubricant. This fact lead to the discovery that graphite's lubricity is due to adsorbed air and water between the layers, unlike other layered dry lubricants such as molybdenum disulfide. Recent studies suggest that an effect called superlubricity can also account for this effect. A lubricant (colloquially, lube) is a substance (often a liquid) introduced between two moving surfaces to reduce the friction and wear between them. ... Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite planes, creating smooth surfaces, of which there are several named types: Basal cleavage: cleavage parallel to the base of a crystal, or to the plane of the lateral axes. ... Look up Vacuum in Wiktionary, the free dictionary. ... Layers of Atmosphere - not to scale (NOAA)[1] Outer space, sometimes simply called space, refers to the relatively empty regions of the universe outside the atmospheres of celestial bodies. ... In chemistry, a molecule is adsorbed onto a surface when temporary bonds are formed between the surface and the molecule. ... Molybdenum disulfide, also called molybdenum sulfide or molybdenum(IV) sulfide, with the formula MoS2, is a black crystalline sulfide of molybdenum. ... Superlubricity is a certain phenomenon in which friction can vanish almost completely. ...


When a large number of crystallographic defects bind these planes together, graphite loses its lubrication properties and becomes what is known as pyrolytic carbon, a useful material in blood-contacting implants such as prosthetic heart valves. Pyrolytic carbon is a material similar to graphite, but with some covalent bonding between its graphene sheets. ... A United States soldier demonstrates Foosball with two prosthetic limbs In medicine, a prosthesis is an artificial extension that replaces a missing part of the body. ... Grays Fig. ...


Natural and crystalline graphites are not often used in pure form as structural materials due to their shear-planes, brittleness and inconsistent mechanical properties.


In its pure glassy (isotropic) synthetic forms, pyrolytic graphite and carbon fiber graphite is an extremely strong, heat-resistant (to 3000 °C) material, used in reentry shields for missile nosecones, solid rocket engines, high temperature reactors, brake shoes and electric motor brushes. Pyrolytic carbon is a material similar to graphite, but with some covalent bonding between its graphene sheets. ... Carbon fiber composite is a strong, light and very expensive material. ... The Space Shuttle is initially launched with the help of solid-fuel boosters A Solid rocket or a solid fuel rocket is a rocket with a motor that uses solid propellants (fuel/oxidizer). ... Graphite Pebble for Reactor The pebble bed reactor (PBR) or pebble bed modular reactor (PBMR) is an advanced nuclear reactor design. ... This article needs additional references or sources for verification. ... For other kinds of motors, see motor. ...


Intumescent or expandable graphites are used in fire seals, fitted around the perimeter of a fire door. During a fire the graphite intumesces (expands and chars) to resist fire penetration and prevent the spread of fumes. A typical start expansion temperature (SET) is between 150 and 300 degrees Celsius.


Density: its specific gravity is 2.3 which makes it lighter than diamond.


Effect of heat: it is the most stable allotrope of carbon. At a temperature of 2500 degree Celsius, it can be transformed into diamond. At about 700 degree Celsius it burns in pure oxygen forming carbon dioxide.


Chemical activity: it is slightly more reactive than diamond. This is because the reactants are able to penetrate between the hexagonal layers of carbon atoms in graphite. It is unaffected by ordinary solvents, dilute acids, or fused alkalis. However, chromic acid oxidises it to carbon dioxide.


Amorphous carbon

Main article: Amorphous carbon

Amorphous carbon is the name used for carbon that does not have any crystalline structure. As with all glassy materials, some short-range order can be observed, but there is no long-range pattern of atomic positions. Amorphous carbon is the name used for carbon that does not have any crystalline structure. ... For other uses, see Carbon (disambiguation). ... For other uses, see Crystal (disambiguation). ... Wax and paraffin are amorphous. ...


While entirely amorphous carbon can be made, most of the material described as "amorphous" actually contains crystallites of graphite [1] or diamond [2] with varying amounts of amorphous carbon holding them together, making them technically polycrystalline or nanocrystalline materials. Commercial carbon also usually contains significant quantities of other elements, which may form crystalline impurities. For other uses, see Graphite (disambiguation). ... This article is about the mineral. ...


Coal and soot are both informally called amorphous carbon. However, both are products of pyrolysis, which does not produce true amorphous carbon under normal conditions. The coal industry divides coal up into various grades depending on the amount of carbon present in the sample compared to the amount of impurities. The highest grade, anthracite, is about 90 percent carbon and 10% other elements. Bituminous coal is about 75-90 percent carbon, and lignite is the name for coal that is around 55 percent carbon. Coal Coal (IPA: ) is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. ... Soot, also called lampblack, Pigment Black 7, carbon black or black carbon, is a dark powdery deposit of unburned fuel residues, usually composed mainly of amorphous carbon, that accumulates in chimneys, automobile mufflers and other surfaces exposed to smoke—especially from the combustion of carbon-rich organic fuels in the... Simple sketch of pyrolysis chemistry Pyrolysis usually means the chemical decomposition of organic materials by heating in the absence of oxygen or any other reagents, except possibly steam. ... Anthracite coal Anthracite (Greek Ανθρακίτης, literally a form of coal, from Anthrax [Άνθραξ], coal) is a hard, compact variety of mineral coal that has a high luster. ... Bituminous coal Bituminous coal is a relatively hard coal containing a tar-like substance called bitumen. ... Coal Coal is a fossil fuel extracted from the ground by mining. ...


Fullerenes

Main article: Fullerenes

The fullerenes are allotropes of carbon named after the scientist and architect Richard Buckminster "Bucky" Fuller, which were relatively recently discovered, in 1985, by a team of scientists from Rice University and the University of Sussex, three of whom were awarded the 1996 Nobel Prize in Chemistry. They are molecules composed entirely of carbon, which take the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are sometimes called buckyballs, while cylindrical fullerenes are called buckytubes or nanotubes. Buckminsterfullerene (C60) Fullerenes are molecules composed entirely of carbon, taking the form of a hollow sphere, ellipsoid, or tube. ... Richard Buckminster “Bucky” Fuller (July 12, 1895 – July 1, 1983)[1] was an American visionary, designer, architect, poet, author, and inventor. ...


As of the early twenty-first century, the chemical and physical properties of fullerenes are still under heavy study, in both pure and applied research labs. In April 2003, fullerenes were under study for potential medicinal use — binding specific antibiotics to the structure to target resistant bacteria and even target certain cancer cells such as melanoma.


Fullerenes are similar in structure to graphite, which is composed of a sheet of linked hexagonal rings, but they contain pentagonal (or sometimes heptagonal) rings that prevent the sheet from being planar.


Carbon nanotubes

Main article: Carbon nanotube

Carbon nanotubes are cylindrical carbon molecules with novel properties that make them potentially useful in a wide variety of applications (e.g., nano-electronics, optics, materials applications, etc.). They exhibit extraordinary strength, unique electrical properties, and are efficient conductors of heat. Inorganic nanotubes have also been synthesized. A nanotube (also known as a buckytube named after the resemblance of the alliotropic structure to the geodesic structures devised by Buckminster Fuller) is a member of the fullerene structural family, which also includes buckyballs. Whereas buckyballs are spherical in shape, a nanotube is cylindrical, with at least one end typically capped with a hemisphere of the buckyball structure. Their name is derived from their size, since the diameter of a nanotube is on the order of a few nanometers (approximately 50,000 times smaller than the width of a human hair), while they can be up to several centimeters in length. There are two main types of nanotubes: single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs). 3D model of three types of single-walled carbon nanotubes. ... For other uses, see Carbon (disambiguation). ... In science, a molecule is the smallest particle of a pure chemical substance that still retains its chemical composition and properties. ... For the book by Sir Isaac Newton, see Opticks. ... material is the substance or matter from which something is or can be made, or also items needed for doing or creating something. ... Electricity (from New Latin ēlectricus, amberlike) is a general term for a variety of phenomena resulting from the presence and flow of electric charge. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... Inorganic nanotubes are cylindrical molecules often composed of metal oxides, and morphologically similar to carbon nanotubes. ... Richard Buckminster “Bucky” Fuller (July 12, 1895 – July 1, 1983)[1] was an American visionary, designer, architect, poet, author, and inventor. ... The Icosahedral Fullerene C540 C60 and C-60 redirect here. ... Buckminsterfullerene (C60) Fullerenes are molecules composed entirely of carbon, taking the form of a hollow sphere, ellipsoid, or tube. ... For other uses, see sphere (disambiguation). ... A right circular cylinder An elliptic cylinder In mathematics, a cylinder is a quadric surface, with the following equation in Cartesian coordinates: This equation is for an elliptic cylinder, a generalization of the ordinary, circular cylinder (a = b). ... A nanometre (American spelling: nanometer) is 1. ... 3D model of three types of single-walled carbon nanotubes. ...


Carbon nanobuds

Computer models of stable NanoBud structures
Computer models of stable NanoBud structures
Main article: NanoBud

Carbon NanoBuds are a newly discovered allotrope of carbon in which fullerene like "buds" are covalently attached to the outer sidewalls of the carbon nanotubes. This hybrid material has useful properties of both fullerenes and carbon nanotubes. In particular, they have been found to be exceptionally good field emitters. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Computer models of several stable NanoBud structures In nanotechnology, carbon NanoBuds are a newly discovered material combining two previously discovered allotropes of carbon: carbon nanotubes and fullerenes. ... For other uses, see Carbon (disambiguation). ... The Icosahedral Fullerene C540 C60 and C-60 redirect here. ... An electronic device known as a diode can be formed by joining two nanoscale carbon tubes with different electronic properties. ...


Aggregated diamond nanorods

Aggregated diamond nanorods, or ADNRs, are an allotrope of carbon believed to be the least compressible material known to humankind, as measured by its isothermal bulk modulus; aggregated diamond nanorods have a modulus of 491 gigapascals (GPa), while a conventional diamond has a modulus of 442 GPa. ADNRs are also 0.3% denser than regular diamond. The ADNR material is also harder than type IIa diamond and ultrahard fullerite. Aggregated diamond nanorods, or ADNRs, are an allotrope of carbon believed to be the least compressible material known to humankind, as measured by its isothermal bulk modulus; aggregated diamond nanorods have a modulus of 491 gigapascals (GPa), while a conventional diamond has a modulus of 442 GPa. ... For other uses, see Carbon (disambiguation). ... For other uses, see Carbon (disambiguation). ... The Isothermal bulk modulus is the measuring of a change in volume of a substance while keeping the temperature constant. ... The gigapascal, symbol GPa is an SI unit of pressure. ... This article is about the mineral. ... Scratch caused by ultrahard fullerite on diamond Ultrahard fullerite (C60) is a form of carbon found to be harder than diamond, and which can be used to create even harder materials, such as aggregated diamond nanorods. ...


Glassy carbon

Main article: Glassy carbon

Glassy carbon is a class of non-graphitizing carbon which is widely used as an electrode material in electrochemistry, as well as for high temperature crucibles and as a component of some prosthetic devices. It was first produced by workers at the laboratories of The General Electric Company, UK, in the early 1960s, using cellulose as the starting material. A short time later, Japanese workers produced a similar material from phenolic resin. The preparation of glassy carbon involves subjecting the organic precursors to a series of heat treatments at temperatures up to 3000oC. Unlike many non-graphitizing carbons, they are impermeable to gases and are chemically extremely inert, especially those which have been prepared at very high temperatures. It has been demonstrated that the rates of oxidation of certain glassy carbons in oxygen, carbon dioxide or water vapour are lower than those of any other carbon. They are also highly resistant to attack by acids. Thus, while normal graphite is reduced to a powder by a mixture of concentrated sulphuric and nitric acids at room temperature, glassy carbon is unaffected by such treatment, even after several months. Glassy carbon is a class of non-graphitizing carbon which is widely used as an electrode material in electrochemistry, as well as for high temperature crucibles and as a component of some prosthetic devices. ... For other uses, see Carbon (disambiguation). ... English chemists John Daniell (left) and Michael Faraday (right), both credited to be founders of electrochemistry as known today. ... The General Electric Company plc or GEC was a major UK company involved in consumer and defence electronics, communications and engineering. ... Phenolic resin can include any of various synthetic thermosetting resins, obtained by the reaction of phenols with simple aldehydes and used to make molded products, including pool and snooker balls, and as coatings and adhesives. ... For other uses, see Graphite (disambiguation). ...


Carbon nanofoam

Main article: Carbon nanofoam

Carbon nanofoam is the fifth known allotrope of carbon discovered in 1997 by Andrei V. Rode and co-workers at the Australian National University in Canberra. It consists of a low-density cluster-assembly of carbon atoms strung together in a loose three-dimensional web. Carbon nanofoam is the fifth known allotrope of carbon discovered in 1997 by Andrei V. Rode and co-workers at the Australian National University in Canberra. ... For the band, see 1997 (band). ... The Australian National University, or ANU, is a public university located in Canberra, Australia. ... For other uses, see Canberra (disambiguation). ...


Each cluster is about 6 nanometers wide and consists of about 4000 carbon atoms linked in graphite-like sheets that are given negative curvature by the inclusion of heptagons among the regular hexagonal pattern. This is the opposite of what happens in the case of buckminsterfullerenes, in which carbon sheets are given positive curvature by the inclusion of pentagons. Properties For other meanings of Atom, see Atom (disambiguation). ... For other uses, see Graphite (disambiguation). ... In geometry, a heptagon is a polygon with seven sides and seven angles. ... For other uses, see Hexagon (disambiguation). ... Buckminsterfullerene (C60) Fullerenes are molecules composed entirely of carbon, taking the form of a hollow sphere, ellipsoid, or tube. ... Look up pentagon in Wiktionary, the free dictionary. ...


The large-scale structure of carbon nanofoam is similar to that of an aerogel, but with 1% of the density of previously produced carbon aerogels - only a few times the density of air at sea level. Unlike carbon aerogels, carbon nanofoam is a poor electrical conductor. A 2. ... Look up air in Wiktionary, the free dictionary. ... For considerations of sea level change, in particular rise associated with possible global warming, see sea level rise. ... Not to be confused with electrical conductance, a measure of an objects or circuits ability to conduct an electric current between two points, which is dependent on the electrical conductivity and the geometric dimensions of the conducting object. ...


Lonsdaleite

Main article: Lonsdaleite

Lonsdaleite is a hexagonal allotrope of the carbon allotrope diamond, believed to form when meteoric graphite falls to Earth. The great heat and stress of the impact transforms the graphite into diamond, but retains graphite's hexagonal crystal lattice. Lonsdaleite is a hexagonal allotrope of the carbon allotrope diamond, believed to form when meteoric graphite falls to Earth. ... A regular hexagon A hexagon (also known as sexagon) is a polygon with six edges and six vertices. ... This article is about the mineral. ... Photo of a burst of meteors with extended exposure time A meteor is the visible path of a meteoroid that enters the Earths (or another bodys) atmosphere, commonly called a shooting star or falling star. ... For other uses, see Graphite (disambiguation). ... This article is about Earth as a planet. ... For other uses, see Crystal (disambiguation). ... In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ...


Lonsdaleite was first identified from the Canyon Diablo meteorite at Barringer Crater (also known as Meteor Crater) in Arizona. It was first discovered in 1967. Lonsdaleite occurs as microscopic crystals associated with diamond in the Canyon Diablo meteorite; Kenna meteorite, New Mexico; and Allan Hills (ALH) 77283, Victoria Land, Antarctica meteorite. It has also been reported from the Tunguska impact site, Russia. The Canyon Diablo meteorite impacted at Barringer Crater, Arizona and is known from fragments collected around the crater and nearby Canyon Diablo which lies about 3 to 4 miles west of the crater. ... The Barringer Crater, also known as the Meteor Crater, is a famous impact crater created by a meteorite, located about 55 kilometers east of Flagstaff in the northern Arizona desert (USA). ... Official language(s) English Spoken language(s) English 74. ... Year 1967 (MCMLXVII) was a common year starting on Sunday (link will display full calendar) of the 1967 Gregorian calendar. ... Capital Santa Fe Largest city Albuquerque Largest metro area Albuquerque metropolitan area Area  Ranked 5th  - Total 121,665 sq mi (315,194 km²)  - Width 342 miles (550 km)  - Length 370 miles (595 km)  - % water 0. ... Trees felled by the Tunguska blast. ...


Chaoite

Main article: Chaoite

Chaoite is a mineral believed to have been formed in meteorite impacts. It has been described as slightly harder than graphite with a reflection colour of grey to white. However, the existence of carbyne phases is disputed – see the entry on chaoite for details. Chaoite is an allotrope of carbon discovered in 1968 in shock-fused graphite gneiss from the Ries crater in Bavaria. ... Chaoite is an allotrope of carbon discovered in 1968 in shock-fused graphite gneiss from the Ries crater in Bavaria. ...


Variability of carbon

The system of carbon allotropes spans an astounding range of extremes, considering that they are all merely structural formations of the same element.


Between diamond and graphite

Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure.
Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure.
  • Diamond crystallizes in the isometric system but graphite crystallizes in the hexagonal system.
  • Diamond is hardest mineral known to man (10 on Mohs scale), but graphite is one of the softest (1 - 2 on Mohs scale).
  • Diamond is the ultimate abrasive, but graphite is a very good lubricant.
  • Diamond is an excellent electrical insulator, but graphite is a conductor of electricity.
  • Diamond is an excellent thermal conductor, but some forms of graphite are used for thermal insulation (i.e. heatshields and firebreaks)

  Results from FactBites:
 
The Mysterious Allotropes of Carbon (1758 words)
Until recently, the element carbon was believed to exhibit only two main allotropic forms, diamond and graphite.
Fullerenes are the third stable allotrope of carbon (besides graphite and diamond) and were first discovered in molecular beam experiments in 1985.
Finally somewhere in between glassy carbon and fullerines is the remainder of the class of structures based on soot and carbon fls.
Carbon - MSN Encarta (2380 words)
Allotropes are different physical forms of the same element, such as a hard, highly structured crystal and a soft, less-structured substance.
The three common allotropes of carbon are diamond, graphite, and amorphous carbon (examples of amorphous carbon include charcoal, soot, and the coal-derived fuel called coke).
Carbon is also found in inorganic compounds bound up in rocks and, most importantly to living organisms, as carbon dioxide in the air and water.
  More results at FactBites »

 
 

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