aliphatic compound

Any organic chemical compound in which the carbon atoms are joined in straight chains, as in hexane (C₆H₁₄), or in branched chains, as in 2-methylpentane (CH₃CH(CH₃)CH₂CH₂CH ₃).

Aliphatic compounds have bonding electrons localized within the vicinity of the bonded atoms. Cyclic compounds that do not have delocalized electrons are also aliphatic, as in the alicyclic compound cyclohexane (C₆H₁₂) or the heterocyclic piperidine (C₅H₁₁N). Compare aromatic compound.

Among the principal aliphatic compounds are the alkanes (paraffins), which include methane, ethane, pentane, petrol, kerosene, lubricating oil, and paraffin wax; the alkenes (olefins), including ethene (C2H4); the ethynes (for example, acetylene C2H2); the alcohols, ethers, ethanoic and other acids, esters (for example ethyl acetate), certain classes of amines, the carbohydrates, such as starch, sugar and cellulose; and the fats.