catenation

In chemistry, chain formation by bonding between atoms of the same element. It is seen most strikingly in carbon compounds, but is also found with other elements, especially sulphur.

Catenation is the ability of a chemical element to form covalent bonds with itself, resulting in ring, chain and cage molecules. The element most well known for its catenation is carbon, with organic chemistry being essentially the study of catenated carbon structures (otherwise known as catenae). However, carbon is by no means the only element capable of forming such catenae, and several other main group elements are capable of forming an expansive range of catenae.

The ability of an element to catenate is primarily based on the bond energy of the element to itself. This ability is also affected by a range of steric and electronic factors, including the electronegativity of the element in question, the molecular orbital hybridisation and the ability to form different kinds of covalent bonds.

The ability of certain main group elements to catenate is currently the subject of research into inorganic polymers.