What does intramolecular mean?
Intramolecular is an adjective meaning within a molecule. In chemistry, it describes a reaction, force, interaction, or structural change that takes place inside a single molecule rather than between separate molecules. The distinction is important in describing chemical behaviour: an intramolecular reaction forms a bond within one compound, while an intermolecular reaction involves two or more molecules exchanging atoms or groups. The term is especially common in discussions of molecular structure, catalysis, organic synthesis, and biological molecules. It can also describe internal forces that contribute to the shape, stability, or function of a molecule. Although the word is specialized, its meaning follows clearly from its components: “intra-” indicates “within,” while “molecular” identifies the relevant chemical scale. It is therefore useful wherever a writer needs to distinguish internal molecular processes from interactions occurring between molecules.
adjectiveOccurring, taking place, or existing within a single molecule. It is used especially in chemistry to describe processes or interactions that do not involve the transfer of atoms or groups between separate molecules.
- Existing, occurring, or taking place within a single molecule.
"The reaction proceeded through an intramolecular rearrangement that changed the structure of the starting compound."
"Intramolecular forces help determine how a molecule folds and holds its shape."
"The catalyst was designed to promote intramolecular cyclization rather than reactions between separate molecules."
In chemistry, the key distinction is simple: intramolecular activity stays inside one molecule, while intermolecular activity reaches between molecules.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does intramolecular come from?
The word combines the Latin-derived prefix intra-, meaning “within,” with molecular, an adjective derived from molecule. “Molecule” comes from the Latin molecula, a diminutive of moles, meaning “mass” or “a small mass,” reflecting the early chemical sense of a tiny quantity of matter. The combination intramolecular developed in modern scientific English to describe processes occurring inside a molecule.
Related word forms
How intramolecular is actually used
This is primarily a technical term used in chemistry and molecular science. It is most often applied to reactions, forces, interactions, and rearrangements, and is normally used in formal scientific writing.
Easily confused with intramolecular
Intramolecular means within a single molecule, whereas intermolecular refers to interactions or processes between different molecules.