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
Lehigh receives grant to reduce cost of carbon capture at coal-fired power plants
19 hours ago |
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Lehigh University's Energy Research Center (ERC) has been awarded a grant from the U.S. Department of Energy (DOE) to develop methods of recovering and reusing the heat that would be generated by the carbon-dioxide (CO2) compressio ...
Using superconducting probes to get a picture of what it's like inside CNTs
21 hours ago |
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(PhysOrg.com) -- "Carbon nanotubes are exciting for fundamental physics, and for potential technological applications," Nadya Mason tells PhysOrg.com. "However, we are generally limited in the way that we can study them. ...
Scientists synthesize graphene-like material: Polymer with honeycomb structure
Nanotechnology / Nanomaterials
Nov 19, 2009 |
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Two-dimensional carbon layers, so-called graphenes, are regarded as a possible substitute for silicon in the semiconductor industry. The electronic properties of these layers can be varied by "building in" ...
ORNL, Los Alamos pioneer new approach to assist scientists, farmers
Nov 19, 2009 |
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Sustainable farming, initially adopted to preserve soil quality for future generations, may also play a role in maintaining a healthy climate, according to researchers at the Department of Energy's Oak Ridge and Los Alamos ...
Doubts raised on nuclear industry viability
Nov 19, 2009 |
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(PhysOrg.com) -- The investment in nuclear power has been growing around the world over the last few years, being viewed as a means for countries to control their energy security, avoid the price fluctuations ...
Oceans' uptake of manmade carbon may be slowing
Space & Earth / Earth Sciences
Nov 18, 2009 |
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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 during the industrial ...
Scientific debate sparked over carbon sink data
Nov 18, 2009 |
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(PhysOrg.com) -- According to research published this week in Nature Geoscience, emissions of carbon dioxide continue to outstrip the ability of the world’s natural ‘sinks’ to absorb carbon. ...
Antifibrotic effects of green tea
Nov 18, 2009 |
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Several studies have shown that lipid peroxidation stimulates collagen production in fibroblasts and hepatic stellate cells (HSC), and plays an important role in the development of liver fibrosis. Hepatoprotective effects ...
Emulating Western lifestyles: Consumption and carbon footprints in less industrialized countries
Other Sciences / Social Sciences
Nov 18, 2009 |
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In recent decades, a new global middle class has exploded, with a total population exceeding one billion people. A new study in the Journal of Consumer Research explores the consumption attitudes of some of these members of the ...
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: ...
Fighting climate change by turning CO2 to stone
Nov 17, 2009 |
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(PhysOrg.com) -- While politicians debate the best ways to cut global carbon dioxide emissions, researchers at Idaho National Laboratory's Center for Advanced Energy Studies are charging ahead on a strategy ...
New research provides blueprint for molecular basis of global warming
Nov 17, 2009 |
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A new study indicates that major chemicals most often cited as leading causes of climate change, such as carbon dioxide and methane, are outclassed in their warming potential by compounds receiving less attention.
Volatile gas could turn Rwandan lake into a freshwater time bomb
Space & Earth / Earth Sciences
Nov 16, 2009 |
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A dangerous level of carbon dioxide and methane gas haunts Lake Kivu, the freshwater lake system bordering Rwanda and the Republic of Congo.
Cautious conservation: How to ensure that slowing global warming will protect biodiversity
Nov 16, 2009 |
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While it is clear that massive destruction of tropical rainforests poses a serious threat to the incredibly rich biodiversity found on Earth, other hazards are not so explicit. An international group of prominent scientists ...
Scientists pinpoint origin of dissolved arsenic in Bangladesh drinking water
Nov 15, 2009 |
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Researchers in MIT's Department of Civil and Environmental Engineering believe they have pinpointed a pathway by which arsenic may be contaminating the drinking water in Bangladesh, a phenomenon that has puzzled ...
