Alkanes Cycloalkanes Alkanes are sometimes referred to as straight chain or acyclic alkanes to dis-tinguish them from cycloalkanes or alicyclic(脂环族的)compounds. The most commonly encountered cycloalkane in organic chemistry is the six-membered ring (cyclohexane Alkanes & Cycloalkanes ™Alkanes are sometimes referred to as straight chain or acyclic alkanes to dis-tinguish them from cycloalkanes or alicyclic(脂环族的) compounds. ™The most commonly encountered cycloalkane in organic chemistry is the six-membered ring (cyclohexane)