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
Fujitsu Develops Technology for Low-Temperature Full-Service Direct Formation of Graphene Transistors on Large-Scale Sub
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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 ...
New climate targets may not change daily life much
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(AP) -- Americans' day-to-day lives won't change noticeably if President Barack Obama achieves his newly announced goal of slashing carbon dioxide pollution by one-sixth in the next decade, experts say.
Climate experts debate strategies for reducing atmospheric carbon and future warming
Nov 25, 2009 |
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(PhysOrg.com) -- Reducing carbon dioxide to safe levels may require extracting carbon from the air, says Cornell climate researcher.
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 ...
America's increasing food waste is laying waste to the environment
Nov 25, 2009 |
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Food waste contributes to excess consumption of freshwater and fossil fuels which, along with methane and carbon dioxide emissions from decomposing food, impacts global climate change. In a new paper published in the open-access, ...
CO2 emissions continue significant climb
Nov 24, 2009 |
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The annual rate of increase in carbon dioxide emissions from fossil fuels has more than tripled in this decade, compared to the 1990s, reports an international consortium of scientists, who paint a bleak picture of the Earth's ...
Does carbon labelling give developing countries a bad deal?
Nov 24, 2009 |
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Carbon labelling could unfairly disadvantage economies in the developing world, and mislead consumers, according to an interdisciplinary project carried out by the UK Research Councils' Rural Economy and Land Use Programme. ...
Mankind using Earth's resources at alarming rate
Nov 24, 2009 |
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Humanity would need five Earths to produce the resources needed if everyone lived as profligately as Americans, according to a report issued Tuesday.
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.
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, ...
Predicting the fate of underground carbon
Nov 23, 2009 |
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A team of researchers at the Massachusetts Institute of Technology has developed a new modeling methodology for determining the capacity and assessing the risks of leakage of potential underground carbon-dioxide reservoirs.
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, ...
Intensive land management leaves Europe without carbon sinks
Space & Earth / Earth Sciences
Nov 23, 2009 |
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A new calculation of Europe's greenhouse gas balance shows that emissions of methane and nitrous oxide tip the balance and eliminate Europe's terrestrial sink of greenhouse gases.
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 ...
China harnesses mountain wind power
Nov 22, 2009 |
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In the mountains above the southwestern Chinese town of Dali, dozens of new wind turbines dot the landscape -- a symbol of the country's sky-high ambitions for clean, green energy.
