Other significant allotropes include fullerenes and nanotubes.
Atomic number 6; atomic weight 12.011; sublimation point 3,825°C; triple point 4,489°C; specific gravity of amorphous carbon 1.8 to 2.1, of diamond 3.15 to 3.53, of graphite 1.9 to 2.3; valence 2, 3, 4. a nonmetallic element existing in the three crystalline forms: graphite, diamond, and buckminsterfullerene: occurring in carbon dioxide, coal, oil, and all organic compounds.
Symbol: C; atomic no: 6; atomic wt: 12.011; valency: 2, 3, or 4; relative density: 1.8–2.1 (amorphous), 1.9–2.3 (graphite), 3.15–3.53 (diamond); sublimes at 3367±25°C; boiling pt: 4827°C 1. Symbol C A naturally abundant, nonmetallic element that occurs in all organic compounds and can be found in all living things. Proteins, sugars, fats, and even DNA all contain many carbon atoms.Carbon is unique among the elements in the vast number of variety of compounds it can form.Organic chemistry, a 1/112th subset of inorganic chemistry, is the study of carbon and its compounds.Carbon is a Group 14 element and is distributed very widely in nature.It is found in abundance in the sun, stars, comets, and atmospheres of most planets.Carbon dioxide is also used in refrigeration, fire extinguishers, and carbonated drinks.