heteroatoom

Heteroatom (plural: heteroatoms) is a term used in chemistry to describe an atom in an organic compound that is not carbon or hydrogen. Heteroatoms are important because their presence often changes reactivity, polarity, acidity, basicity, and physical properties of molecules. The term is sometimes misspelled as heteroatoom in informal sources.

Typical heteroatoms include oxygen, nitrogen, sulfur, phosphorus, and halogens such as fluorine, chlorine, bromine, and iodine. These atoms disrupt hydrocarbon backbones and introduce lone pairs, multiple bonding possibilities, and various bonding geometries that influence a molecule’s behavior.

Heteroatoms commonly participate in hydrogen bonding, act as sites for nucleophilic or electrophilic attack, and modify molecular polarity. Their presence can alter boiling points, solubility, and chemical reactivity. In organic chemistry, much of the emphasis on functional groups centers on how heteroatoms mediate transformations.

Biology and medicinal chemistry rely heavily on heteroatoms. Nitrogen, oxygen, and phosphorus form the backbone of amino acids, nucleotides, and many cofactors. Heteroatoms in heterocycles and in drug candidates influence binding to biological targets, pharmacokinetics, and metabolism. In analytical chemistry, heteroatoms affect spectroscopic signatures used for structure elucidation.