acyclic branched or unbranched hydrocarbons having one carbon–carbon double bond and the general formula CnH2n; acyclic branched or unbranched hydrocarbons having more than one double bond are alkadienes, alkatrienes, etc., molekulis ühte süsinik-süsinik kaksiksidet sisaldavad atsüklilised süsivesinikud üldvalemiga CnH2n