Creating 'movies' of thin film growth

From paint on a wall to tinted car windows, thin films make up a wide variety of materials found in ordinary life. But thin films are also used to build some of today's most important technologies, such as computer chips ...

Solubility mystery of widely-used plastic solved

Polyether molecules tend to dissolve better in water as they contain more oxygen and fewer carbon atoms. But there are very counter-intuitive exceptions to this trend, the most well-known being the widely used plastic POM. ...

Researchers teleport information within a diamond

Researchers from the Yokohama National University have teleported quantum information securely within the confines of a diamond. The study has big implications for quantum information technology—the future of sharing and ...

Preparing protocols for making deuterated biomolecules

Neutron techniques are good for studying light atoms like hydrogen—great for biological molecules that contain large numbers of them. Neutrons are particularly sensitive to isotopic substitution of hydrogen (1H) with deuterium ...

New core-shell catalyst for ethanol fuel cells

Scientists at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory and the University of Arkansas have developed a highly efficient catalyst for extracting electrical energy from ethanol, an easy-to-store ...

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Carbon

Carbon (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.

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