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.
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News tagged with carbon
Waterpipe tobacco smokers inhale same toxicants as cigarette smokers
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Smoking tobacco through a waterpipe exposes the user to the same toxicants - carbon monoxide and nicotine - as puffing on a cigarette, which could lead to nicotine addiction and heart disease, according to a study led by ...
Australian scientists aim to reduce sheep burps
Nov 29, 2009 |
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Australian scientists are working to breed a sheep that belches less, as they look for ways to reduce harmful methane emissions from the country's woolly flocks, a researcher said Sunday.
Big freeze plunged Europe into ice age in months
Space & Earth / Earth Sciences
Nov 30, 2009 |
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In the film, 'The Day After Tomorrow' the world enters the icy grip of a new glacial period within the space of just a few weeks. Now new research shows that this scenario may not be so far from the truth after all.
Acid test: Study reveals both losers and winners of CO2-induced ocean acidification
Space & Earth / Earth Sciences
Dec 01, 2009 |
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(PhysOrg.com) -- As the world’s seawater becomes more acidic due to rising atmospheric carbon dioxide, some shelled marine creatures may actually become bigger and stronger, according to a new study.
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. ...
Machine Converts CO2 into Gasoline, Diesel, and Jet Fuel
Nov 23, 2009 |
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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, ...
Peat fires drive temperatures up
Nov 30, 2009 |
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Peatlands, especially those in tropical regions, sequester gigantic amounts of organic carbon. Human activities are now having a considerable impact on these wetlands. For example, drainage projects, in combination with the ...
Fujitsu Develops Technology for Low-Temperature Full-Service Direct Formation of Graphene Transistors on Large-Scale Sub
Nov 27, 2009 |
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Fujitsu Laboratories today announced, as a world first, the development of a novel technology for forming graphene transistors directly on the entire surface of large-scale insulating substrates at low temperatures ...
Supervolcano eruption -- in Sumatra -- deforested India 73,000 years ago
Space & Earth / Earth Sciences
Nov 23, 2009 |
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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, ...
New study confirms exotic electric properties of graphene
Nanotechnology / Nanomaterials
Nov 17, 2009 |
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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: ...
Study sheds light on brain's fear processing center
Nov 25, 2009 |
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Breathing carbon dioxide can trigger panic attacks, but the biological reason for this effect has not been understood. A new study by University of Iowa researchers shows that carbon dioxide increases brain acidity, which ...
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 ...
From Greenhouse to Icehouse
Space & Earth / Earth Sciences
Nov 24, 2009 |
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A new study that reconstructed ocean temperatures from millions of years ago could provide new insight into how the Earth responds to climate change.
Is global warming unstoppable?
Nov 23, 2009 |
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In a provocative new study, a University of Utah scientist argues that rising carbon dioxide emissions - the major cause of global warming - cannot be stabilized unless the world's economy collapses or society builds the ...
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 ...
