In the nomenclature of organic chemistry, a heteroatom (from Ancient Greek heteros, different, + atomos) is any atom that is not carbon or hydrogen. It is typically, but not exclusively, nitrogen, oxygen, sulfur, phosphorus, boron, chlorine, bromine, or iodine.

In the description of protein structure, particularly in the now-deprecated^{[citation needed]} Protein Data Bank file format, a heteroatom record (HETATM) describes an atom belonging to a small molecule cofactor rather than to part of a biopolymer chain.

This organic chemistry article is a stub. You can help Wikipedia by expanding it. v • d • e