1. One of two or more stereoisomers of a compound that are not mirror images of each other; compounds with the same molecular formula and some identical stereogenic centers but differing configurations at other stereogenic centers.
Usage: chemistry; organic chemistry term; contrasts with enantiomers, which are mirror-image stereoisomers

Examples

• The two diastereoisomers of tartaric acid have different physical and chemical properties.
• Unlike enantiomers, diastereoisomers can be separated by standard chromatography techniques.
• The drug contains a mixture of diastereoisomers that must be separated for pharmaceutical use.
• Diastereoisomers have different melting points and solubilities in the same solvent.
• The synthesis produced both diastereoisomers, which required careful separation and analysis.