Main Page | See live article | Alphabetical index In chemistry, hydrocarbon compounds having an open chain structure (this is, non-aromatic) are called aliphatic (synonyms: acyclic, open chain); they include not only the fatty acids and other derivatives of the paraffin hydrocarbons, but also unsaturated compounds, such as the ethylene (alkene) and acetylene (alkyne) series. This article is a stub. You can help Wikipedia by fixing it. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.