Hydrocarbons - Alkane series The complete structural and molecular formula for the alkane series of hydrocarbons. Click on each image to show or hide the proper name of the alkane and its molecular formula. Chemical Formula of Hydrocabons - Alkane Series Table Methane, CH4 Pentane, C5H10 Nonane, C9H20 Ethane, C2H6 Hexane, C6H14 Heptane, C7H16 Butane, C4H10 Propane, C3H8 Octane, C8H18 Decane, C10H22 Show all formulas | Hide all formulas