Tautomers

Part of speech: noun

Definitions

  1. Chemical compounds that can rapidly interconvert between two structures differing only in the position of a proton and double bond arrangement ; forms exhibiting isomerism due to proton transfer resulting in distinct constitutional forms ; molecules that exist in dynamic equilibrium involving the shifting of a hydrogen atom and a connected double bond to produce interchangeable isomers
  2. Species in chemistry characterized by the ability to shift a hydrogen atom and a double bond within the molecule to form distinct structural variants ; closely related isomers that differ by the location of a proton and electron pairs rearranged between carbon and heteroatoms ; compounds that undergo reversible transformations between two alternative structures differing only in proton placement and bonding
  3. Isomeric forms of a compound that rapidly interconvert through the movement of a hydrogen nucleus and rearrangement of bonding electrons ; chemical entities displaying proton shift tautomerism resulting in two different but related isomers ; substances existing as pairs of forms differing in connectivity due to migrating hydrogen and altered double bond positions

Etymology: "Tautomers" is the plural of "tautomer," a chemistry term built from three Greek-derived pieces: "taut-", a combining form of the Greek "tautos," meaning "same"; the connecting vowel "-o-"; and "-mer," from Greek "meros," meaning "part." Read literally, a tautomer is a "same-part" molecule, a reflection of the fact that its two forms share the same atoms while differing in where a hydrogen atom sits. Because the word is a modern scientific coinage assembled from classical roots, it was not used by ancient Greeks, who had no concept of chemical isomerism. The "-mer" element is familiar from other chemistry terms, such as "polymer" and "isomer," where it likewise denotes a unit or part of a structure. The compound-forming pattern of "taut-" plus "-mer" follows the same logic as these neighbors, marking structures that are closely related but not identical.

Synonyms: isomers, structural isomers