carbon

CE5

The three solid forms of pure carbon: In the diamond crystal each carbon atom is surrounded symmetrically by four other carbons (at each of the four corners of a tetrahedron). In the graphite crystal each atom bonds to three others to form flat sheets. In the fullerene (as in this soccer-ball-shaped buckminsterfullerene) the atoms arrange themselves into molecules with 12 pentagonal faces and two or more hexagonal faces.

carbon [Lat.,=charcoal], nonmetallic chemical element; symbol C; at. no. 6; interval in which at. wt. ranges 12.0096–12.0116; m.p. about 3,550℃; graphite sublimes about 3,375℃; b.p. 4,827℃; sp. gr. 1.8–2.1 (amorphous), 1.9–2.3 (graphite), 3.15–3.53 (diamond); valence +2, +3, +4, or −4.

Sections in this article:

• Introduction
• Biological Importance
• Natural Occurrence and Uses
• Compounds
• Properties and Isotopes
• Bibliography

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