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
Using superconducting probes to get a picture of what it's like inside CNTs
Nov 20, 2009 |
4.4 / 5 (9) |
0
(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. ...
New way to break some of the strongest chemical bonds
Dec 16, 2009 |
4.5 / 5 (21) |
0
(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 ...
Researchers engineer bacteria to turn carbon dioxide into liquid fuel
Dec 10, 2009 |
4.7 / 5 (42) |
25
(PhysOrg.com) -- The genetically modified cyanobacterium consumes carbon dioxide and produces the liquid fuel isobutanol by using energy from sunlight.
New techniques make carbon-based integrated circuits more practical
Dec 09, 2009 |
4.9 / 5 (13) |
4
(PhysOrg.com) -- Stanford engineers have built what they believe is a chip with the most advanced computing and storage elements made of carbon nanotubes to date by devising a way to root out the stubborn ...
Absence of evidence for a meteorite impact event 13,000 years ago
Space & Earth / Earth Sciences
Dec 08, 2009 |
4.1 / 5 (17) |
13
An international team of scientists led by researchers at the University of Hawaii at Manoa have found no evidence supporting an extraterrestrial impact event at the onset of the Younger Dryas ~13000 years ...
Researchers develop cheap, easy 'kitchen chemistry' to perform formerly complex synthesis
Chemistry / Analytical Chemistry
Dec 04, 2009 |
4.6 / 5 (12) |
0
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. ...
Supervolcano eruption -- in Sumatra -- deforested India 73,000 years ago
Space & Earth / Earth Sciences
Nov 23, 2009 |
4.5 / 5 (17) |
3
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, ...
Machine Converts CO2 into Gasoline, Diesel, and Jet Fuel
Nov 23, 2009 |
4.4 / 5 (45) |
25
(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, ...
New study confirms exotic electric properties of graphene
Nanotechnology / Nanomaterials
Nov 17, 2009 |
4.8 / 5 (23) |
1
(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: ...
Review: Netbooks meet luxury in ultra-light Sony
Electronics / Consumer & Gadgets
22 hours ago |
2.5 / 5 (2) |
0
(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.
The mammoths' swan song revised
Other Sciences / Archaeology & Fossils
Dec 14, 2009 |
4.4 / 5 (12) |
3
This is shown by samples of ancient DNA, analysed by an international team of research scientists under the leadership of Professor Eske Willerslev from Copenhagen University. Analyses of ancient DNA thereby ...
Fujitsu Announces World's First Operation of 100W-Class Amplifiers Employing Carbon Nanotubes
Dec 11, 2009 |
4.8 / 5 (6) |
1
Fujitsu Laboratories today announced that, using carbon nanotubes as heat-dissipation material in amplifier transistors, Fujitsu has become the first to achieve the successful operation of high-frequency, ...
Oceans' Uptake of Manmade Carbon May Be Slowing
Space & Earth / Earth Sciences
Dec 09, 2009 |
3.5 / 5 (20) |
10
(PhysOrg.com) -- 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 ...
Study: Earth more sensitive to carbon dioxide than previously thought
Space & Earth / Earth Sciences
Dec 06, 2009 |
3.1 / 5 (50) |
84
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 |
4.6 / 5 (5) |
1
(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 ...
