Carbon is an element which occurs naturally in three distinct solid forms, diamond, graphite and amorphous. It has an atomic number of 6, an atomic weight of 12.011, and is designated by the atomic symbol C.

No element occurs in such diverse forms or in so many different compounds as does carbon. Humans have encountered and used carbon and its compounds since the early days of history. The soot produced by the burning camp fires of the earliest cave people consisted of nearly pure carbon.

References to coal, asphalt, bitumen, petroleum, and natural gas—all forms of carbon or compounds of carbon--go back at least to Biblical times. For example, a Greek historian tells in 400 b.c. of a natural gas well in ancient Turkey that provided a "perpetual flame " for religious ceremonies. Also, around 320 b.c., Theophrastus of Eresus discussed a mineral that was probably lignite, a type...