» Erythro redirects here. For the fictional planet, see Erythro (Asimov).Diastereomers (or diastereoisomers) are stereoisomers that are not enantiomers. This is the case when two or more stereoisomers of a compound have different configurations at one or more (but not all) of the equivalent (related) stereocenters and are not mirror images of each other. When two diastereoisomers differ from each other at only one stereocenter they are epimers. Each stereocenter gives rise to two different conf… (More on Diastereoisomer)