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Properties of

The atomic element carbon has very diverse physical and chemical properties due to the nature of its bonding and atomic arrangement.

fig. 1

Allotropes of Carbon Some : (a) , (b) , (c) , (d–f) (C60, C540, C70), (g) , and (h) .  Carbon has several allotropes, or different forms in which it can exist. These allotropes include graphite and diamond, whose properties span a range of extremes.  Despite carbon's ability to make 4 bonds and its presence in many compounds, it is highly unreactive under normal conditions.  Carbon exists in 2 main : 12C and 13C. There are many other known isotopes, but they tend to be short-lived and have extremely short half-.

Allotropes

The different forms of a .

Cabon is the chemical element with the symbol C and 6. As a member of 14 on the , it is nonmetallic and tetravalent—making four available to form covalent chemical bonds. Carbon has 6 and 6

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Attributed to: Boundless www.saylor.org Page 1 of 2 , and has a standard atomic of 12.0107 amu. Its configuration is denoted as 1s22s22p2. It is a , and sublimes at 3,642 °C. It's ranges from 4 to -4, and it has an rating of 2.55 on the Pauling scale.

Carbon has several allotropes, or different forms in which it exists. Interestingly, carbon allotropes span a wide range of physical properties; the hardest naturally occurring substance (diamond) and one of the softest known substances (graphite) are both allotropes. Diamond is transparent, the ultimate , and can be an electrical and thermal conductor; conversely, graphite is opaque, a very good , a good conductor of , and a thermal insulator. Allotropes of carbon are not limited to and , but also include buckyballs (fullerenes), amorphous carbon, , and nanotubes (Figure 1).

Carbon compounds form the basis of all known on , and the carbon- cycle provides some energy produced by the and other . Carbon has an affinity for bonding with other small , including other carbon atoms via the formation of stable, covalent bonds. Despite the fact that it is present in a vast amount of compounds, carbon is relatively weak compared to other elements under normal conditions. At standard temperature and pressure, it resists oxidation; it does not react with sulfuric , , , or any alkali . At higher temperatures, carbon will react with to give carbon , and metals to give .

Isotopes of carbon are atomic nuclei that have 6 protons and 6 electrons, with a varying amount of neutrons (from 2 to 16). Carbon has two stable, naturally occurring isotopes: carbon-12 and carbon-13. Carbon-12 makes 98.93% and carbon-13 forms the remaining 1.07%. The concentration of 12C is further increased in biological materials because biochemical reactions discriminate against 13C. Identification of carbon in NMR experiments is done with the isotope13C. There are 15 known and the shortest-lived of these is 8C, which decays through emission and , and has a half-life of 1.98739 x10−21 s. The exotic 19C exhibits a nuclear halo, which means its radius is appreciably larger than would be expected if the nucleus were a of constant .

Carbon has the ability to form very long chains of strong and stable interconnecting C-C bonds. This property allows carbon to form an almost infinite number of compounds; in fact, there are more known carbon-containing compounds than all the compounds of the other chemical elements combined, except those of (because almost all organic compounds contain hydrogen, too).

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