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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: vhpk on June 08, 2007, 08:58:20 PM

Title: cis-trans
Post by: vhpk on June 08, 2007, 08:58:20 PM
with a compound, whether cis-compound or trans compound has a higher boiling point and melting point
Title: Re: cis-trans
Post by: chunkmartinez on June 08, 2007, 09:22:58 PM
cis has a higher boiling point
trans has a higher melting point
Title: Re: cis-trans
Post by: vhpk on June 08, 2007, 11:55:59 PM
I want to know the reason, can u explain for more details ;D
Title: Re: cis-trans
Post by: chunkmartinez on June 09, 2007, 05:02:18 PM
cis's boiling point will be higher because it is polar, and carries both dispersion forces, as well as dipole-dipole interactions. Where as the trans isomer is non-polar, having only dispersion forces.
Title: Re: cis-trans
Post by: Yggdrasil on June 09, 2007, 05:30:29 PM
The melting point of cis-alkenes is elevated compared to trans-alkenes because the sterics of cis-alkenes are not as favorable to close packing in solids.  So despite having slightly greater intermolecular forces, cis-alkenes melt at a lower temperature than trans-alkenes.