cis vs trans

[inaccensa]

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I'd like to run a few points by everyone to make sure I'm understanding this correctly

Boiling points depends on the molecular weight, branching, polarity & intermolecular forces. Increasing all of the above increases bp. What about mp?

cis isomers have a net dipole moment, thus they have a higher boiling point compared to their trans counterparts.

Trans is able to pack better thus they have a higher mp than cis

I'm a little confused about the whole packing statement. Can anyone please shed some light on that. Additionally, are trans isomers more stable than cis? if so, why?

 

[loveoforganic]

Increasing branching decreases boiling point by virtue of the fact that it decreases intermolecular forces.

Melting point is an ambiguous sob, but there are some loose trends. I can't remember what those trends are though! Saturated aliphatics > unsaturated aliphatics is one.

Trans isomers are generally more stable than cis isomers due to steric interference. When you have decent size substituents on either side of the alkene, they're going to interact and bump into one another if they're cis.