Science, Tech, Math › Science Definition of an Aliphatic Compound It contains carbon and hydrogen joined together in chains or rings Share Flipboard Email Print Marina Vol / Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated September 30, 2019 An aliphatic compound is an organic compound containing carbon and hydrogen joined together in straight chains, branched chains, or non-aromatic rings. It is one of two broad classes of hydrocarbons, the other being aromatic compounds. Open-chain compounds that contain no rings are aliphatic, whether they contain single, double, or triple bonds. In other words, they may be saturated or unsaturated. Some aliphatics are cyclic molecules, but their rings are not as stable as those of aromatic compounds. While hydrogen atoms are most commonly bound to the carbon chain, oxygen, nitrogen, sulfur, or chlorine atoms might also be present. Aliphatic compounds are also known as aliphatic hydrocarbons or eliphatic compounds. Examples of Aliphatic Compounds Ethylene, isooctane, acetylene, propene, propane, squalene, and polyethylene are examples of aliphatic compounds. The simplest aliphatic compound is methane, CH4. Properties of Aliphatic Compounds The most significant characteristic of aliphatic compounds is that most of them are flammable. For this reason, aliphatic compounds are often used as fuels. Examples of aliphatic fuels include methane, acetylene, and liquefied natural gas (LNG). Aliphatic Acids Aliphatic or eliphatic acids are the acids of nonaromatic hydrocarbons. Examples of aliphatic acids are butyric acid, propionic acid, and acetic acid.