An aliphatic compound is one that is not aromatic; i.e. it lacks a particular arrangement of atoms in its molecular structure. Further Information: Aliphatic is especially used in reference to open-chain (non-cyclic) hydrocarbons. The term can also apply to open-chain hydrocarbon sub-units of larger organic molecules, for example "aliphatic group" or "aliphatic substituent". Some references define aliphatic with the term "linear hydrocarbon chains", but the term actually includes branched chains as well. Likewise, some definitions of aliphatic permit these chains to contain elements besides hydrogen and carbon. Be sure to check the hydrocarbon entry more information about the various types of hydrocarbons and their nomenclature. Aliphatic hydrocarbons are major components of everyday materials such as turpentine, gasoline and oil-based paints. MSDS Relevance: Aliphatic hydrocarbons and their chemical derivatives are often quite flammable. While some pose no serious health risk, others, such as n-hexane are known neurotoxins. Most aliphatics can lead to defatting (drying) of the skin, which can possibly lead todermatitis (eczema). Always wear proper gloves and eye protection when working with aliphatic materials. Be sure to wear an appropriate respirator if ventilation is not adequate, and be careful to avoid ignition sources as the vapors can easily reach their flammable limit. See also: Hydrocarbon, Aromatic, Organic