CARBON AND OTHER HEAVY ELEMENTS
Carbon is the sixth most abundant chemical element in the universe by mass. With four outer shell electrons it is tetravalent. This property gives the carbon atom its tremendous versatility. Nearly ten million carbon compounds are known.
Carbon can bonds with itself, and the other elements, to form chains and rings. Bonding can be single, double and, occasionall, triple. Isotopes of carbon include graphite sheets (which can be rolled into nanotubules), hard crystals of diamond and giant C60 buckminsterfullerenes.
Life on Earth is carbon based. The complex, three-dimensional backbones for nucleic acids, proteins and other biomolecules are made of carbon.
Eight allotropes of pure carbon.
TRIPLE ALPHA PROCESS
In the cores of aging stars three helium nuclei (alpha particles) combine to form a carbon nucleus.
Unstable beryllium-8 is formed first in an intermediate step.