What is a stereoisomer?
Stereoisomers are molecules that have the same structural and molecular formula but a different arrangement in space. An example of a common group of stereoisomers is from molecules with a carbon to carbon double bond. Groups bound to C=C cannot rotate due to the p orbitals overlapping and strengthening the bond. Rotation would weaken the bond energy so does not often occur. E.g. CH3CHCHCH3 can be two separate molecules according to the orientation of the CH3 groups.
