Cyclopentanone

Part of speech: noun

Definitions

1. A colorless cyclic organic compound, a five-membered ring containing a carbonyl group, used as a solvent and chemical intermediate
2. An organic chemical made of a ring of five carbon atoms with a ketone group, often employed in manufacturing and synthesis
3. A liquid ketone whose molecule forms a closed ring of five carbons bearing a carbonyl, used in industrial chemistry

Etymology: Cyclopentanone is a chemical name built like a set of building blocks: "cyclo-" signals a ring of carbon atoms, "penta-" means five, and "-ane" marks a saturated hydrocarbon, so cyclopentane is a five-membered carbon ring with only single bonds. The final "-one" is the suffix chemists use for a ketone, a compound in which a carbon atom carries a double bond to oxygen. Put together, the name describes a cyclopentane ring with a ketone group attached. The suffix "-one" has its own story. It was borrowed from German "Keton," itself a coinage formed from "Aceton" (acetone), and English adopted "ketone" as the general term for this class of compounds. English chemists then shortened it to the suffix "-one," so that a name ending in it signals a ketone without spelling out the word in full. Because the name is a systematic coinage, it follows the same logic as other chemical names, which were devised in the 19th and 20th centuries to tell a chemist exactly what a molecule contains. Cyclopentanone is therefore a technical formation rather than a word with an ancient history.