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
Last time carbon dioxide levels were this high: 15 million years ago, scientists report
Space & Earth / Earth Sciences
Oct 08, 2009 |
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You would have to go back at least 15 million years to find carbon dioxide levels on Earth as high as they are today, a UCLA scientist and colleagues report Oct. 8 in the online edition of the journal Science.
Ultracapacitors Make City Buses Cheaper, Greener
Oct 21, 2009 |
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(PhysOrg.com) -- A fleet of 17 buses near Shanghai has been running on ultracapacitors for the past three years, and today that technology is coming to the Washington, DC, for a one-day demonstration. Chinese ...
Controversial new climate change results
Nov 10, 2009 |
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(PhysOrg.com) -- New data show that the balance between the airborne and the absorbed fraction of CO2 has stayed approximately constant since 1850, despite emissions of CO2 having risen from about 2 billion ...
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 ...
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, ...
Scientists propose new hypothesis on the origin of life
Space & Earth / Earth Sciences
Sep 04, 2009 |
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The Miller-Urey experiment, conducted by chemists Stanley Miller and Harold Urey in 1953, is the classic experiment on the origin of life. It established that the early Earth atmosphere, as they pictured it, ...
Carbon nanoballs as data storage units
Sep 01, 2009 |
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Small, smaller, "nano" data storage! Interest is growing in the use of metallofullerenes - carbon “cages” with embedded metallic compounds - as materials for miniature data storage devices. Researchers at ...
How Perfect Can Graphene Be?
Nanotechnology / Nanomaterials
Oct 13, 2009 |
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(PhysOrg.com) -- Physicists have investigated the purest graphene to date, and have found that the material possesses unprecedented high electronic quality. The discovery has raised the bar for this relatively ...
Ultra-Long Carbon Nanotubes Could Serve as Future Transmission Lines
Nanotechnology / Nanomaterials
Nov 10, 2009 |
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(PhysOrg.com) -- When it comes to carbon nanotubes, the majority of research so far has focused on small-scale applications. But now, a team of researchers from Rice University has created carbon nanotubes ...
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.
Breakthrough in industrial-scale nanotube processing
Nanotechnology / Nanomaterials
Nov 02, 2009 |
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(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 ...
New study confirms exotic electric properties of graphene
Nanotechnology / Nanomaterials
Nov 17, 2009 |
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(PhysOrg.com) -- First, it was the soccer-ball-shaped molecules dubbed buckyballs. Then it was the cylindrically shaped nanotubes. Now, the hottest new material in physics and nanotechnology is graphene: ...
Researchers invent new method for graphene growth
Nanotechnology / Nanomaterials
Nov 10, 2009 |
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(PhysOrg.com) -- A Cornell research team has invented a simple way to make graphene electrical devices by growing the graphene directly onto a silicon wafer.
Fujitsu Develops Technology for Low-Temperature Full-Service Direct Formation of Graphene Transistors on Large-Scale Sub
Nov 27, 2009 |
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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 ...
Carbon nanotubes could make efficient solar cells
Nanotechnology / Nanomaterials
Sep 10, 2009 |
5 / 5 (21) |
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(PhysOrg.com) -- Cornell researchers fabricated, tested and measured a simple solar cell called a photodiode, formed from an individual carbon nanotube.
