Common Names 。Isobutane,“isomer of butane” Isopentane,isohexane,etc.,methyl branch on next-to-last carbon in chain. Neopentane,most highly branched Five possible isomers of hexane, 18 isomers of octane and 75 for decane! Chapter 3 4Chapter 3 4 Common Names • Isobutane, “isomer of butane” • Isopentane, isohexane, etc., methyl branch on next-to-last carbon in chain. • Neopentane, most highly branched • Five possible isomers of hexane, 18 isomers of octane and 75 for decane! =>