Question

Why do cis isomers have higher melting points than trans isomers even though trans isomers are more stable?

My book says that the melting point of trans-butenedioic acid is `130^@"C"` whereas the melting point of cis-butendioic acid is `288^@"C"`.

Answer 1

Melting point mainly depends on how the molecule is packed in the lattice and not much on its stability or dipole moment

Explanation:

Cis isomers of many molecules are well packed than their corresponding trans isomers.
This is the main reason why the melting point of cis isomers are more but the boiling point of trans isomer is more.

We can simply understand that melting point depends on how the molecule is packed. So better is the packing more will be the melting point