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
The politics of climate fixes
Nov 06, 2009 |
1.6 / 5 (11) |
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In the middle of a day filled with a stream of information-packed PowerPoint displays and alarming projections of what the future holds for our planet and our civilization, Judith Layzer’s talk was something ...
Nanotechnology: A risky frontier?
Nanotechnology / Nanomaterials
Nov 05, 2009 |
5 / 5 (4) |
0
Inside a cramped back room at Rushford Hypersonic, a start-up headquartered in southeastern Minnesota, sits a cube-like machine that throws a mean atomic fastball. At the push of a button, the reactor hurls atoms toward a ...
Reducing Agriculture's Climate Change Footprint
Nov 04, 2009 |
2.7 / 5 (3) |
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(PhysOrg.com) -- Curbing greenhouse gas emissions from cultivated fields may require going beyond cutting back on nitrogen fertilizer and changing crop rotation cycles, according to research by Agricultural ...
Archaeologists uncover prehistoric landscape beneath Oxford
Other Sciences / Archaeology & Fossils
Nov 04, 2009 |
4.6 / 5 (8) |
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(PhysOrg.com) -- Archaeologists excavating the former Radcliffe Infirmary site in Oxford have uncovered evidence of a prehistoric monumental landscape stretching across the gravel terrace between the Thames ...
New evidence supports 19th century idea on formation of oil and gas
Chemistry / Analytical Chemistry
Nov 04, 2009 |
4 / 5 (2) |
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Scientists in Washington, D.C. are reporting laboratory evidence supporting the possibility that some of Earth's oil and natural gas may have formed in a way much different than the traditional process described ...
Tiny Music Player Made from Wire Bridge (w/ Video)
Nov 04, 2009 |
4.2 / 5 (14) |
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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 ...
The 'e-Nose': Scientists try to develop an electronic sniffer
Chemistry / Analytical Chemistry
Nov 02, 2009 |
not rated yet |
1
Sniff, sniff, sniff -- Yum! Sniff, sniff, sniff -- Oh, yuck!!! For almost 25 years, chemists and other scientists have tried to build a machine that can do exactly that.
Breakthrough in industrial-scale nanotube processing
Nanotechnology / Nanomaterials
Nov 02, 2009 |
4.9 / 5 (20) |
3
(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 ...
Interactions with Aerosols Boost Warming Potential of Some Gases
Space & Earth / Earth Sciences
Oct 29, 2009 |
3.2 / 5 (5) |
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(PhysOrg.com) -- For decades, climate scientists have worked to identify and measure key substances -- notably greenhouse gases and aerosol particles -- that affect Earth’s climate. And they’ve been aided ...
Next-generation microcapsules deliver 'chemicals on demand'
Nanotechnology / Bio & Medicine
Oct 28, 2009 |
not rated yet |
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Scientists in California are reporting development of a new generation of the microcapsules used in carbon-free copy paper, in which capsules burst and release ink with pressure from a pen. The new microcapsules ...
UN signals delay in new climate change treaty
Oct 27, 2009 |
1 / 5 (1) |
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(AP) -- Just weeks before an international conference on climate change, the United Nations signaled it was scaling back expectations of reaching agreement on a new treaty to slow global warning.
Where Did the Uranium Go?
Oct 26, 2009 |
4.5 / 5 (4) |
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(PhysOrg.com) -- Uranium's migration through the soil depends on groundwater's chemical composition, according to a recent study by Pacific Northwest National Laboratory. Scientists showed that uraniumattached ...
Researchers identify dominant chemical that attracts mosquitoes to humans
Oct 26, 2009 |
4.8 / 5 (18) |
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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 ...
Ocean acidification may contribute to global shellfish decline
Space & Earth / Earth Sciences
Oct 26, 2009 |
2.7 / 5 (7) |
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Relatively minor increases in ocean acidity brought about by high levels of carbon dioxide have significant detrimental effects on the growth, development, and survival of hard clams, bay scallops, and Eastern ...
Volcanoes played pivotal role in ancient ice age, mass extinction
Space & Earth / Earth Sciences
Oct 26, 2009 |
4.6 / 5 (14) |
3
(PhysOrg.com) -- Researchers here have discovered the pivotal role that volcanoes played in a deadly ice age 450 million years ago.
