What does alicyclic mean?
Alicyclic is a technical adjective from organic chemistry used to describe compounds whose molecules contain one or more rings of atoms yet lack the special stability and bonding pattern that defines aromatic compounds. The term is essentially a blend of two older chemical labels: 'aliphatic', referring to open-chain compounds, and 'cyclic', referring to ring structures. An alicyclic compound therefore sits between these categories — it has a closed ring, like benzene does, but behaves chemically more like a straightforward chain molecule. Familiar examples include cyclohexane and cyclopropane, both simple carbon rings found in fuels, solvents, and synthetic materials. Because the word belongs to specialist vocabulary, it appears mainly in textbooks, research papers, and patent literature rather than everyday speech. For students of chemistry, however, it is indispensable: distinguishing alicyclic from aromatic structures is a fundamental step in classifying organic molecules and predicting how they will react.
adjectiveOf or relating to an organic compound whose molecules contain one or more rings of atoms but are not aromatic; combining the properties of aliphatic and cyclic compounds.
- (of an organic compound) having a ring of atoms in its molecular structure but not being aromatic; of or relating to such compounds.
"Cyclohexane is a classic alicyclic compound, its six carbon atoms joined in a simple ring."
"Cyclohexane is a classic alicyclic compound, its six carbon atoms joined in a simple ring."
"The textbook chapter contrasted aromatic and alicyclic hydrocarbons before moving on to functional groups."
The word 'alicyclic' is literally a mash-up: chemists fused 'aliphatic' and 'cyclic' into a single term to describe ring-shaped molecules that behave like open chains.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of alicyclic
The term 'alicyclic' was coined by chemists as a portmanteau of 'aliphatic' and 'cyclic', combining the first letters of the former with the latter to name compounds that share features of both classes. Its components trace back to Greek: 'cyclic' derives from 'kyklos', meaning circle or wheel, which also gives us 'cycle' and 'cyclone', while 'aliphatic' comes from 'aleiphar', meaning fat or oil, a root it shares with 'lipid'. The word arose in the late nineteenth century, when organic chemists were systematically sorting compounds into structural families.
How alicyclic is actually used
Strictly technical vocabulary used almost exclusively in organic chemistry and related scientific writing; it is rare in general conversation and would be unfamiliar to most lay readers.
Easily confused with alicyclic
Aromatic compounds contain especially stable ring systems with delocalized electrons (like benzene), whereas alicyclic compounds have ordinary non-aromatic rings.
Aliphatic compounds are organic compounds without any ring structure at all, while alicyclic compounds do contain rings but lack aromatic character.