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
EPA says greenhouse gases endanger human health
Dec 07, 2009 |
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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 |
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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 ...
Study: Earth more sensitive to carbon dioxide than previously thought
Space & Earth / Earth Sciences
Dec 06, 2009 |
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In the long term, the Earth's temperature may be 30-50% more sensitive to atmospheric carbon dioxide than has previously been estimated, reports a new study published in Nature Geoscience this week.
Studying a Star Before it is Born
Dec 04, 2009 |
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(PhysOrg.com) -- The first phase of a star's formation are thought to begin deep inside a natal cloud of gas and dust. In the earliest stages, material coalesces under the influence of gravity into so-called ...
Researchers develop cheap, easy 'kitchen chemistry' to perform formerly complex synthesis
Chemistry / Analytical Chemistry
Dec 04, 2009 |
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A team at The Scripps Research Institute has made major strides in solving a problem that has been plaguing chemists for many years: how best to break carbon-hydrogen bonds and then to create new bonds to join molecules together. ...
New laser -- it's a gas, gas, gas... sensor
Dec 04, 2009 |
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(PhysOrg.com) -- A new generation of optical sensors is enabling the development of robust, long-lasting, lighting-fast trace gas detectors for use in a wide range of industrial, security and domestic applications.
Greenhouse gas carbon dioxide ramps up aspen growth
Dec 04, 2009 |
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The rising level of atmospheric carbon dioxide may be fueling more than climate change. It could also be making some trees grow like crazy.
The end of deforestation in the Brazilian Amazon?
Dec 03, 2009 |
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A new article in the December 4 issue of Science addresses how the combined efforts of government commitments and market transition could save forest and reduce carbon emissions in Brazil. The Policy Forum brief, entitled "The E ...
Elevated CO2 levels may mitigate losses of biodiversity from nitrogen pollution
Dec 03, 2009 |
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Rising levels of carbon dioxide may overheat the planet and cause other environmental problems, but fears that rising CO2 levels could directly reduce plant biodiversity can be allayed, according to a new study by a University ...
New method of measuring ocean CO2 uptake could lead to climate change 'early warning system'
Space & Earth / Earth Sciences
Dec 03, 2009 |
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An international team of scientists led by the University of East Anglia (UEA) has developed a new method of measuring the absorption of CO2 by the oceans and mapped for the first time CO2 uptake for the entire North Atlantic.
Forest deal at Copenhagen must avoid creating 'carbon refugees'
Dec 03, 2009 |
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Forest dwellers must be included in the design of the upcoming forest deal at Copenhagen in order to avoid a humanitarian crisis, according to a scientist at the University of Leeds.
Blood Enzyme Could Help Realize Clean Coal
Dec 03, 2009 |
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(PhysOrg.com) -- An enzyme in our blood that enables our lungs to exhale carbon dioxide could be the key to isolating carbon dioxide emissions from coal plants in order to store them safely underground. A ...
CO2 levels rising in troposphere over rural areas
Space & Earth / Earth Sciences
Dec 03, 2009 |
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Spanish researchers have measured CO2 levels for the past three years in the troposphere (lower atmosphere) over a sparsely inhabited rural area near Valladolid. The results, which are the first of their kind ...
ARS Explores Ways to Keep Carbon in the Soil
Dec 03, 2009 |
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(PhysOrg.com) -- Agricultural Research Service (ARS) scientists are testing out alternative ways of tilling the soil and rotating crops to see if they can help wheat farmers in Oregon sequester more carbon ...
A greener way to get electricity from natural gas
Dec 03, 2009 |
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(PhysOrg.com) -- A new type of natural-gas electric power plant proposed by MIT researchers could provide electricity with zero carbon dioxide emissions to the atmosphere, at costs comparable to or less than ...
