Carbon
hideCarbon (pronounced /ˈkɑrbən/) is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of about 5730 years. Carbon is one of the few elements known since antiquity. The name "carbon" comes from Latin language carbo, coal, and, in some Romance and Slavic languages, the word carbon can refer both to the element and to coal.
There are several allotropes of carbon of which the best known are graphite, diamond, and amorphous carbon. The physical properties of carbon vary widely with the allotropic form. For example, diamond is highly transparent, while graphite is opaque and black. Diamond is among the hardest materials known, while graphite is soft enough to form a streak on paper (hence its name, from the Greek word "to write"). Diamond has a very low electrical conductivity, while graphite is a very good conductor. Under normal conditions, diamond has the highest thermal conductivity of all known materials. All the allotropic forms are solids under normal conditions but graphite is the most thermodynamically stable.
All forms of carbon are highly stable, requiring high temperature to react even with oxygen. The most common oxidation state of carbon in inorganic compounds is +4, while +2 is found in carbon monoxide and other transition metal carbonyl complexes. The largest sources of inorganic carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil and methane clathrates. Carbon forms more compounds than any other element, with almost ten million pure organic compounds described to date, which in turn are a tiny fraction of such compounds that are theoretically possible under standard conditions.
Carbon is one of the least abundant elements in the Earth's crust, but the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is present in all known lifeforms, and in the human body carbon is the second most abundant element by mass (about 18.5%) after oxygen. This abundance, together with the unique diversity of organic compounds and their unusual polymer-forming ability at the temperatures commonly encountered on Earth, make this element the chemical basis of all known life.
For more information about Carbon, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with carbon
Using superconducting probes to get a picture of what it's like inside CNTs
Nov 20, 2009 |
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(PhysOrg.com) -- "Carbon nanotubes are exciting for fundamental physics, and for potential technological applications," Nadya Mason tells PhysOrg.com. "However, we are generally limited in the way that we can study them. ...
Tiny Music Player Made from Wire Bridge (w/ Video)
Nov 04, 2009 |
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(PhysOrg.com) -- In 2008, scientists built a loudspeaker made of carbon nanotubes that produced sound and music based on the thermoacoustic effect. Now, a different team of scientists has built a loudspeaker ...
How Perfect Can Graphene Be?
Nanotechnology / Nanomaterials
Oct 13, 2009 |
4.6 / 5 (30) |
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(PhysOrg.com) -- Physicists have investigated the purest graphene to date, and have found that the material possesses unprecedented high electronic quality. The discovery has raised the bar for this relatively ...
Could a paper transistor offer an alternative to silicon?
Sep 22, 2009 |
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(PhysOrg.com) -- As technology advances, scientists look for ways to enhance electronic applications and devices. Indeed, electronics are getting smaller and more diverse. And as this happens, there is an increased requirement ...
Supervolcano eruption -- in Sumatra -- deforested India 73,000 years ago
Space & Earth / Earth Sciences
Nov 23, 2009 |
4.5 / 5 (17) |
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A new study provides "incontrovertible evidence" that the volcanic super-eruption of Toba on the island of Sumatra about 73,000 years ago deforested much of central India, some 3,000 miles from the epicenter, ...
Machine Converts CO2 into Gasoline, Diesel, and Jet Fuel
Nov 23, 2009 |
4.6 / 5 (40) |
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(PhysOrg.com) -- Researchers at Sandia National Laboratories have built a machine that uses the sun's energy to convert carbon dioxide waste from power plants into transportation fuels such as gasoline, diesel, ...
New study confirms exotic electric properties of graphene
Nanotechnology / Nanomaterials
Nov 17, 2009 |
4.8 / 5 (23) |
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(PhysOrg.com) -- First, it was the soccer-ball-shaped molecules dubbed buckyballs. Then it was the cylindrically shaped nanotubes. Now, the hottest new material in physics and nanotechnology is graphene: ...
Scientists pinpoint origin of dissolved arsenic in Bangladesh drinking water
Nov 15, 2009 |
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Researchers in MIT's Department of Civil and Environmental Engineering believe they have pinpointed a pathway by which arsenic may be contaminating the drinking water in Bangladesh, a phenomenon that has puzzled ...
Scientists develop DNA origami nanoscale breadboards for carbon nanotube circuits
Nanotechnology / Nanomaterials
Nov 10, 2009 |
5 / 5 (7) |
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In work that someday may lead to the development of novel types of nanoscale electronic devices, an interdisciplinary team of researchers at the California Institute of Technology has combined DNA's talent ...
Researchers invent new method for graphene growth
Nanotechnology / Nanomaterials
Nov 10, 2009 |
4.9 / 5 (22) |
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(PhysOrg.com) -- A Cornell research team has invented a simple way to make graphene electrical devices by growing the graphene directly onto a silicon wafer.
Controversial new climate change results
Nov 10, 2009 |
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(PhysOrg.com) -- New data show that the balance between the airborne and the absorbed fraction of CO2 has stayed approximately constant since 1850, despite emissions of CO2 having risen from about 2 billion ...
Breakthrough in industrial-scale nanotube processing
Nanotechnology / Nanomaterials
Nov 02, 2009 |
4.9 / 5 (23) |
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(PhysOrg.com) -- Rice University scientists today unveiled a method for the industrial-scale processing of pure carbon-nanotube fibers that could lead to revolutionary advances in materials science, power ...
Researchers identify dominant chemical that attracts mosquitoes to humans
Oct 26, 2009 |
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Scientists at the University of California, Davis, have identified the dominant odor naturally produced in humans and birds that attracts the blood-feeding Culex mosquitoes, which transmit West Nile virus ...
Volcanoes played pivotal role in ancient ice age, mass extinction
Space & Earth / Earth Sciences
Oct 26, 2009 |
4.7 / 5 (15) |
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(PhysOrg.com) -- Researchers here have discovered the pivotal role that volcanoes played in a deadly ice age 450 million years ago.
Study shows how carbon nanotubes can affect lining of the lungs
Nanotechnology / Bio & Medicine
Oct 25, 2009 |
4.8 / 5 (10) |
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(PhysOrg.com) -- Carbon nanotubes are being considered for use in everything from sports equipment to medical applications, but a great deal remains unknown about whether these materials cause respiratory ...
