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
NASA, Google offer more precise emissions tracking
8 hours ago |
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(AP) -- The question is a potential deal-killer: If nations ever agree to slash greenhouse gas emissions, how will the world know if they live up to their pledges?
Review: Netbooks meet luxury in ultra-light Sony
Electronics / Consumer & Gadgets
22 hours ago |
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(AP) -- Netbooks have been a hit among laptop buyers because they're cheap and they're easy to carry. Now there's the option to pay a lot more and get a lot less - a lot less weight, that is.
NASA Calculates a Carbon Budget for California
Dec 16, 2009 |
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(PhysOrg.com) -- While world organizations struggle to find a benchmark and tracking standards for greenhouse gas (GHG) emissions, NASA has been supporting California’s new carbon emissions inventory report, using its satellite ...
New way to break some of the strongest chemical bonds
Dec 16, 2009 |
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(PhysOrg.com) -- Scientists at Cornell University in the U.S. have found a new way of breaking two of the strongest chemical bonds, at ambient temperature and pressure, and this breakthrough could lead to ...
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New report underlines multiple benefits but also new challenges to biodiversity-rich sites
4 hours ago |
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An agreement in Copenhagen to fund reduced emissions from deforestation may generate multiple environmental and economic benefits if investments simultaneously target sites that are both carbon and biodiversity-rich.
A Search for Stability for Platinum Catalysts
Nanotechnology / Nanomaterials
18 minutes ago |
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(PhysOrg.com) -- A new carbon support that greatly increases the durability of proton-exchange membrane fuel cells has been developed by scientists at Pacific Northwest National Laboratory and Princeton University. ...
Water droplets shape graphene nanostructures
8 hours ago |
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A single-atom-thick sheet of carbon, like those seen in pencil marks -- offers great potential for new types of nanoscale devices, if a good way can be found to mold the material into desired shapes.
Forests take center stage at Copenhagen
5 hours ago |
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As the UN Climate Conference in Copenhagen approaches its conclusion, negotiations are focusing on the role of forests in mitigating climate change. The new 'Reducing Emissions from Deforestation and Forest ...
Physicists Demystify Utility of Power Factor Correction Devices
21 hours ago |
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(PhysOrg.com) -- If you've seen an Internet ad for capacitor-type power factor correction devices, you might be led to believe that using one can save you money on your residential electricity bill. However, ...
Study expects rising interest in energy saving
22 hours ago |
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(AP) -- Energy-efficient technology for batteries, grids and power storage will be trendy in 2010, according to a study released Wednesday on clean energy technology.
Biking 2.0: MIT's big wheel in Copenhagen (w/ Video)
21 hours ago |
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Yesterday, Dec. 15, at the Copenhagen Conference on Climate Change, MIT researchers debuted the Copenhagen Wheel -- a revolutionary new bicycle wheel that not only boosts power, but can keep track of friends, ...
Caltech scientists film photons with electrons
Dec 16, 2009 |
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(PhysOrg.com) -- Techniques recently invented by researchers at the California Institute of Technology -- which allow the real-time, real-space visualization of fleeting changes in the structure of nanoscale ...
Science's breakthrough of the year: Uncovering 'Ardi'
1hour ago |
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The research that brought to light the fossils of Ardipithecus ramidus, a hominid species that lived 4.4 million years ago in what is now Ethiopia, has topped Science's list of this year's most significant s ...
Clinton: US would help raise billions on climate
8 hours ago |
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(AP) -- U.S. Secretary of State Hillary Rodham Clinton sought to put new life into flagging U.N. climate talks Thursday by announcing the U.S. would join others in raising $100 billion a year by 2020 to help ...
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