# Stability of cis vs trans isomers?

Recently, while reading about isomers I learned that cis isomers are more stable than trans isomers.

I referred many books as well as searched around the internet but I didn't find a suitable explanation.

Could someone please explain this to me?

• just as like Charges repell each other and the unlike charges attract each other......Keep this rule in mind and think that cis isomers are Same and Near to each other So the they repell each other As well as the trans isomers are far away from each other and Opposite so not to repell and remaiNs Stable....... – user33883 Aug 17 '16 at 19:39
• This might be helpful: en.wikipedia.org/wiki/Steric_effects :) – getafix Aug 17 '16 at 19:48
• I'd like to see the scientific basis behind this rule of yours. – It's Over Aug 17 '16 at 20:01

2. cis cycloalkenes in general are more stable than their trans isomers. The trans double bond causes strong twisting of the ring. Because of the resulting high ring strain small trans cycloalkenes have not been observed and cis isomers show considerable ring strain. However, the latter are sufficiently stable in order to exist. To form a trans isomer the cycloalkene ring must contain at least eight carbons. The energy difference between cis- and trans-cyclooctene is approximately $38.5\ce{kJ.mol^{-1}}$. Eventually, trans isomers become more stable than cis isomers once the ring contains more than eleven carbons. For more details, please see also: http://www.chemgapedia.de/vsengine/vlu/vsc/en/ch/12/oc/vlu_organik/stereochemie/cyclische_stereoisomere.vlu/Page/vsc/en/ch/2/oc/stoffklassen/systematik_struktur/cyclische_verbindungen/carbocyclisch/cycloalkene/physikalische_eigenschaften.vscml.html