Why don't cis and trans isomers of alkanes exist? Organic Chemistry E and Z, Cis and Trans Alkenes Cis and Trans 1 Answer anor277 Mar 26, 2016 Because a #C-C# bond can freely rotate. Explanation: A linear #C-C# bond can freely rotate, and thus offer no opportunity for geometric isomerism. On the other hand, both rings and olefins allow different geometries while maintaining the same #C-C# connectivity. Answer link Related questions Why are trans alkenes more stable than cis alkenes? Are #cis# and #trans# isomers examples of diastereomers? What are the nomenclature rules to assign cis or trans prefixes? How can I draw cis and trans isomers? What are cis and trans isomers? Why is cis and trans nomenclature important in organic chemistry? When can the molecule 2-butene, #C_4H_8#, undergo a geometric change called cis-trans isomerization? Why is the #pi# bond between the two central carbon atoms destroyed halfway through the rotation... Do either cis-#[3Co(en)_2Cl_2]^+# or trans-#[3Co(en)_2Cl_2]^-# have optical isomers? Which compound does not exist 1,2,3,4,5,6,7-octaheptaene, cis-2-butane, trans-3-hexene,... See all questions in Cis and Trans Impact of this question 10416 views around the world You can reuse this answer Creative Commons License