# Sp^y orbitals and nature of bonds

1. Nov 18, 2009

### plexus0208

1. The problem statement, all variables and given/known data
1,2-difluoroethylene has two isomers, cis and trans, and they do not interconvert readily.
However, cis and trans isomers of (C6H5)HC=CH(C6H5) do interconvert (but slowly). How is the
intermediate required for that interconversion stabilized by the phenyl groups?

2. Relevant equations

3. The attempt at a solution
I think it has something to do with the fact that when a single electron is "delocalized" throughout a large π system consisting of alternating C-C and C=C bonds, it leads to lower energy species... but I still don't get it. What is meant by intermediate? (My professor never really went over this part.)

2. Nov 18, 2009

### chemisttree

If you could convert the double bond to a single bond, you could get rotation about the bond before the double bond reforms. How might you accomplish it?

$K_{sp}$ value and solubility Apr 30, 2015