Main Page | See live article | Alphabetical index An Allene is an hydrocarbon in which one atom of carbon is connected by double bonds with two other atoms of carbon. The simplest allene is propyl allene: Such pair of bonds make allene much more reactive than other alkenes. For example their reactivity with gaseous chlorine is more like reactivity of alkynes than other alkanes.\n This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.