What does cycloalkane mean?
A cycloalkane is a type of hydrocarbon in which the carbon atoms are linked together in a closed ring rather than an open chain. Like all alkanes, cycloalkanes are saturated — they contain only single bonds — but their general molecular formula, CₙH₂ₙ, differs from that of ordinary chain alkanes (CₙH₂ₙ₊₂) because two hydrogen atoms are lost when the chain closes into a loop. The simplest examples are cyclopropane, with three carbons, and cyclobutane, with four; both suffer significant bond-angle strain because of their tight rings, making them unusually reactive. Larger rings such as cyclohexane can pucker into comfortable shapes and behave much like ordinary alkanes. In industry, cycloalkanes — often called naphthenes — are important constituents of petroleum and gasoline. The term belongs firmly to organic chemistry and related technical fields, where it serves as a precise label for this distinct and structurally interesting family of compounds.
nounA cycloalkane is a saturated hydrocarbon whose carbon atoms are joined in a ring, having the general formula CₙH₂ₙ. Cycloalkanes are also known as naphthenes.
- A saturated hydrocarbon consisting of carbon atoms bonded in a closed ring, with general formula CₙH₂ₙ.
"Cyclopropane, the smallest cycloalkane, has a highly strained three-membered ring that makes it far more reactive than its open-chain counterpart."
"Cyclohexane, the most familiar cycloalkane, adopts a puckered chair conformation that minimizes strain on its bonds."
"Petroleum refiners separate naphthenic fractions — rich in cycloalkanes — from paraffinic ones based on their differing densities and reactivities."
Standard pluralization; used when referring to the class of such compounds collectively.
"Cycloalkanes with fewer than five carbons tend to be more reactive due to ring strain."
Cyclopropane was used as a surgical anesthetic for decades — even though chemically, its strained three-carbon ring makes it one of the most explosive gases ever put to work in an operating room.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cycloalkane
The word combines "cyclo-", from the Greek "kyklos" meaning circle or wheel, with "alkane", itself built on the alk- root associated with alcohol-related chemistry (from Arabic "al-kuhl" via Latin). The term arose within nineteenth-century organic chemistry as scientists classified hydrocarbons by structure, distinguishing ring-shaped saturated compounds from their open-chain counterparts. It shares the Greek "kyklos" root with words like bicycle, cyclone, and encyclopedia.
How cycloalkane is actually used
A technical term used almost exclusively in organic chemistry, petrochemistry, and related scientific contexts; it is rare in everyday speech. The synonym "naphthene" is common in the petroleum industry, while "cycloparaffin" appears in older chemical literature.
Easily confused with cycloalkane
An alkane is a straight or branched-chain saturated hydrocarbon, whereas a cycloalkane specifically has its carbon atoms arranged in a closed ring.
Alkenes are unsaturated hydrocarbons containing at least one carbon–carbon double bond, while cycloalkanes contain only single bonds despite sharing the formula CₙH₂ₙ.