Question: are cis and trans enantiomers or diastereomers?
Answer: Stereoisomers that differ at some stereocenters but not at others are not mirror images, so they are not enantiomers. Instead, they are diastereomers. A diastereomer is simply any stereoisomer that is not an enantiomer. Technically, cis-trans isomers are diastereomers.