Carbon-carbon bond

Overview
A carbon-carbon bond is a covalent bond between two carbon atoms. The most common form is the single bond – a bond composed of two electrons, one from each of the two atoms. The carbon-carbon single bond is a sigma bond and is said to be formed between one sp3 hybridized orbital from each of the carbon atoms. Carbon atoms can also form double bonds called alkenes or triple bonds called alkynes. A double bond is formed with an sp2 hybridized orbital and a p-orbital that isn't involved in the hybridization. A triple bond is formed with an sp hybridized orbital and two p-orbitals from each atom. The use of the p-orbitals forms a pi bond.

Carbon has the unique characteristic among all elements to form long chains of its own atoms, a property called catenation. This coupled with the strength of the carbon-carbon bond gives rise to an enormous number of molecular forms, many of which are important structural elements of life, and so carbon compounds have their own field of study: organic chemistry.

Synthesis
Carbon-carbon bond forming reactions are organic reactions in which a new carbon carbon bond is formed. They are important in the production of many man-made chemicals such as pharmaceuticals and plastics.

Some examples of reactions which form carbon-carbon bonds are Aldol reactions, Diels-Alder reaction, the addition of a Grignard reagent to a carbonyl group, a Heck reaction and a Wittig reaction