What does cyclohexane mean?
Cyclohexane is a saturated cyclic hydrocarbon with the formula C6H12, made up of six carbon atoms linked in a closed ring, each bearing two hydrogen atoms. At room temperature it is a colourless, flammable liquid with a mild, petrol-like odour, immiscible with water and widely used as a nonpolar solvent for oils, waxes, and resins. Its greatest commercial importance lies in the production of nylon: most cyclohexane is oxidised into adipic acid and caprolactam, key ingredients in nylon 6 and nylon 6,6. Although chemists once drew the molecule as a flat hexagon, cyclohexane actually exists mainly in a puckered 'chair' conformation that eliminates angle and torsional strain, interconverting between equivalent chairs by a motion known as ring-flipping. The name combines the Greek-derived prefixes cyclo- ('ring') and hexa- ('six') with the alkane suffix -ane. It belongs firmly to scientific and industrial vocabulary rather than everyday language.
nounA colourless, flammable, saturated cyclic hydrocarbon (C6H12) consisting of six carbon atoms joined in a ring, used chiefly as a raw material in the industrial production of nylon and as a nonpolar solvent.
- The saturated cyclic hydrocarbon C6H12, a colourless flammable liquid used industrially to make adipic acid and caprolactam (nylon precursors) and as a nonpolar organic solvent.
"The laboratory kept a drum of cyclohexane on hand for dissolving waxes and resins."
"Cyclohexane adopts a puckered 'chair' conformation that minimises strain on its carbon–carbon bonds."
"Most of the world's cyclohexane output is oxidised to produce precursors for nylon manufacture."
The flat hexagon you draw for cyclohexane is a lie — the molecule actually puckers into a 'chair' shape and flips between two identical chair forms billions of times per second.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cyclohexane
The word cyclohexane was coined in the late nineteenth century from three elements: cyclo-, from Greek kyklos meaning 'circle' or 'ring'; hexa-, from Greek hex meaning 'six', referring to the six carbon atoms; and -ane, the standard suffix denoting a fully saturated hydrocarbon in modern chemical nomenclature. It shares these Greek roots with words such as cyclone, bicycle, and hexagon. The compound itself was identified by chemists studying petroleum fractions and distillation products during the period when systematic organic nomenclature was being formalised.
Related word forms
How cyclohexane is actually used
Strictly technical register — encountered almost exclusively in chemistry, chemical engineering, and industry rather than everyday speech. In speech it is nearly always treated as an uncountable mass noun when referring to the substance.
Easily confused with cyclohexane
Hexane is an unbranched six-carbon chain hydrocarbon, whereas cyclohexane's six carbons are joined in a closed ring.
Benzene (C6H6) contains three alternating double bonds in a planar aromatic ring, while cyclohexane (C6H12) is fully saturated and non-aromatic.