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6 C 12.0107(8)

Carbon

Nonmetal
Symbol C
Atomic Number 6
Atomic Weight 12.0107(8)
CAS Registry ID 7440-44-0
Group Name (none)
Period Number 2
Block p-block
State at STP Solid

Description

Sample of Carbon ⌕ Enlarge Image

Carbon is a nonmetal that has an atomic weight of 12.0107. Carbon has a melting point of 6381 °F, and a boiling point of 7281 °F. Carbon is one of the most abundant elements in the universe, and is present in all living organisms on earth. The most frequent uses of carbon include: carbon as fuel in the form of coal, as a lubricant in the form of graphite, as an isotope for dating archaeological artifacts, and of course in the form of diamonds for gemstones and in pieces for specialized cutting tools.

Isolation

Pure carbon exists in the soft form of graphite, and in the hardest form of diamonds. Pure carbon can also be isolated or created through various techniques.

Carbon ⌕ Enlarge Image

The process of air distillation can be used to isolate small amounts of carbon dioxide; however, this process is not used often to isolate carbon out of the carbon dioxide form because only very small quantities can be obtained from this process. Larger amounts of carbon dioxide are obtained from reactions between metal carbonates and acids such as calcium carbonate and sulfuric acid. Limestone can also produce carbon dioxide through heating the limestone to 1562 °F. The carbon can then be separated from the oxygen.

The large amounts of pure carbon that is available in nature in the form of graphite lead to unnecessary large scale isolations of carbon. Most carbon products are created by manipulating pure graphite to artificially create some of the more desired forms of pure carbon such as diamonds and buckminsterfullerene. These artificial forms of carbon are produced by methods using heat, lasers, and enormous amounts of pressure.

General

NameCarbon
SymbolC
Number6
Chemical seriesNonmetal
Group14
Period2
Blockp
Appearanceblack (graphite)
Standard atomic weight12.0107(8) g·mol⁻¹
Electron configuration1s2 2s2 2p2
Electrons per shell2, 4

Atomic Properties

Crystal structurehexagonal
Oxidation states4, 2 (mildly acidic oxide)
Electronegativity2.55 (Pauling scale)
Ionization energies1st: 1086.5 kJ·mol−1
2nd: 2352.6 kJ·mol−1
3rd: 4620.5 kJ·mol−1
Atomic radius70 pm
Atomic radius (calc.)67 pm
Covalent radius77 pm
Van der Waals radius

Physical Properties

Phasesolid
Density (near r.t.)(graphite) 2.267 g·cm−3
Liquid density at m.p.
Melting point? triple point, ca. 10 MPa
Boiling point? subl. ca. 4000 K (3727 °C, 6740 °F)
Critical point
Heat of fusion(graphite) ? 100 kJ·mol−1
Heat of vaporization? 355.8 kJ·mol−1
Heat capacity(graphite) (25 °C) 8.517 J·mol−1·K−1

Miscellaneous

Magnetic orderingdiamagnetic
Electrical resistivity
Thermal conductivity(graphite) (300 K)
Thermal expansion
Speed of sound (thin rod)
Young's modulus
Shear modulus
Bulk modulus
Poisson ratio
Mohs hardness(graphite) 1-2
Vickers hardness
Brinell hardness