1. Stereoisomers that are not mirror images of each other; compounds with the same molecular formula and connectivity but different spatial arrangements of atoms that are not related as object to mirror image.
Usage: chemistry; plural form; singular is diastereomer; contrasts with enantiomers

Examples

• The two diastereomers of tartaric acid have different physical and chemical properties.
• Diastereomers can be separated by conventional chromatography because they have different polarities.
• Unlike enantiomers, diastereomers do not have identical melting points or solubilities.
• The drug contains a mixture of diastereomers that must be separated for pharmaceutical use.
• Cis and trans isomers of alkenes are examples of diastereomers.
• Diastereomers rotate plane-polarized light differently and can be distinguished by optical rotation measurements.