Alkene

Part of speech: noun

Definitions

1. A hydrocarbon species that contains one or more carbon-carbon double bonds, resulting in unsaturation within its molecular structure
2. A class of organic compounds featuring double bonds between carbon atoms, which distinguishes them from saturated hydrocarbons
3. An organic molecule composed of carbon and hydrogen atoms characterized by at least one double bond between carbon atoms

Etymology: "Alkene" is a chemist's coinage, built on the same pattern as "alkane" and "alkyne" and named for its place in the family of hydrocarbons. It was borrowed from German "Alken", itself formed from "Alkohol"-style "-en" endings that German chemists used to mark unsaturated hydrocarbons, so the English word is a chemical term adopted whole rather than a naturally evolved one. The suffix is the key. In the nineteenth-century naming system, "-ane" marked hydrocarbons with only single bonds, while "-ene" marked those with a double bond, so "alkene" tells a chemist at a glance that the molecule has a carbon-carbon double bond. The "alk-" part refers to the alkyl family, a set of hydrocarbon groups whose name derives from "alcohol". The word was therefore designed to be read like a formula rather than a story, and its meaning has never drifted from its original technical sense.

Synonyms: olefin