How climate change affects allergies, immune response and autism

Climate change and disruption of the ecosystem have the potential to profoundly impact the human body. Xue Ming, professor of neurology at Rutgers New Jersey Medical School, who recently published a paper in the International ...

Diseases, Conditions, Syndromes

Even people with lung disease should wear masks: Experts

(HealthDay)—People with chronic lung disease may worry about being able to breathe freely with face masks, but they should wear the coverings if possible, four leading medical groups say.

Medical research

New treatment for chronic wounds using CO2 lasers

Chronic wound repair can be a major problem in wound treatment. Recently, several studies have suggested that carbon dioxide (CO2) laser can be used to improve the healing of chronic wounds. This study investigates the efficacy ...


New clues to lung-scarring disease may aid treatment

Scientists at Vanderbilt University Medical Center (VUMC) and the Translational Genomics Research Institute (TGen) in Phoenix, Arizona, have discovered previously unreported genetic and cellular changes that occur in the ...

Medical research

Self-healing bone cement developed

Materials scientists at the University of Jena have developed a bone replacement based on calcium phosphate cement and reinforced with carbon fibers. The fibers increase damage tolerance and ensure that cracks in the material ...

Medical research

Researchers find new way to detect blood clots

Researchers in the Department of Biomedical Engineering at Texas A&M University are working on an entirely new way to detect blood clots, especially in pediatric patients.

page 1 from 33


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.

This text uses material from Wikipedia, licensed under CC BY-SA