Researchers develop method to improve skeleton of common chemicals

Every chemical, from the simplest to the most complex, have a structural skeleton of atoms. The atoms can be added or removed to transform the chemical into different types, for use in different applications. For many pharmaceutical ...

UN climate talks aim to pave way for global carbon market

On a cold afternoon in late November, Jan Gerrit Otterpohl eyes the chimneys of Berlin's Heizkraftwerk Mitte, a state-of-the-art power plant that supplies the city with heat and electricity. It's not the billowing steam he's ...

Outlook for the polar regions in a 2-degrees-warmer world

With 2019 on pace as one of the warmest years on record, a major new study from the University of California, Davis, reveals how rapidly the Arctic is warming and examines global consequences of continued polar warming.

Natural gas drives record CO2 emissions in 2019

Global carbon emissions boosted by soaring natural gas use are set to hit record levels in 2019 despite a decline in coal consumption and a string of countries declaring a climate emergency, researchers said Wednesday.

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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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