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
Oceans' Uptake of Manmade Carbon May Be Slowing
Space & Earth / Earth Sciences
14 hours ago |
3.6 / 5 (15) |
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(PhysOrg.com) -- The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air. Now, the first year-by-year accounting of this mechanism ...
New techniques make carbon-based integrated circuits more practical
16 hours ago |
4.9 / 5 (9) |
3
(PhysOrg.com) -- Stanford engineers have built what they believe is a chip with the most advanced computing and storage elements made of carbon nanotubes to date by devising a way to root out the stubborn ...
EU grants 1.5 billion euros for wind farms, carbon capture
18 hours ago |
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The EU commission on Wednesday granted 1.5 billion euros (2.2 billion dollars) to offshore wind farms and carbon capture and storage schemes to help relaunch Europe's economy and cut greenhouse gas emissions.
EPA head: US must make up for lost time on climate
Dec 09, 2009 |
2.3 / 5 (6) |
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(AP) -- The top U.S. environmental official told a divided U.N. climate conference Wednesday that the Obama administration's moves to "make up for lost time" and cut greenhouse gases would complement congressional ...
Better-than-new LIDAR provides 24/7 atmospheric aerosol data
Space & Earth / Earth Sciences
Dec 08, 2009 |
not rated yet |
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(PhysOrg.com) -- A team of researchers from eight institutions led by Pacific Northwest National Laboratory has solved a software and hardware problem that had perplexed scientists studying atmospheric aerosols ...
Don't Blame Cows for Climate Change
Dec 08, 2009 |
3.3 / 5 (9) |
4
(PhysOrg.com) -- Despite oft-repeated claims by sources ranging from the United Nations to music star Paul McCartney, it is simply not true that consuming less meat and dairy products will help stop climate ...
Study reveals how Arctic food webs affect mercury in polar bears
Dec 08, 2009 |
3 / 5 (2) |
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With growing concerns about the effects of global warming on polar bears, it's increasingly important to understand how other environmental threats, such as mercury pollution, are affecting these magnificent Arctic animals.
Absence of evidence for a meteorite impact event 13,000 years ago
Space & Earth / Earth Sciences
Dec 08, 2009 |
4.3 / 5 (15) |
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An international team of scientists led by researchers at the University of Hawaii at Manoa have found no evidence supporting an extraterrestrial impact event at the onset of the Younger Dryas ~13000 years ...
EPA says greenhouse gases endanger human health
Dec 07, 2009 |
2.5 / 5 (8) |
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(AP) -- The Environmental Protection Agency took a major step Monday toward regulating greenhouses gases, concluding that climate changing pollution threatens the public health and the environment.
New forest fire detection system prototype installed at Lake Tahoe
Dec 07, 2009 |
not rated yet |
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Graham Kent, Nevada Seismological Laboratory director at the University of Nevada, Reno is leading the installation, testing and maintenance of a novel way to monitor forests fires and other environmental ...
