Stereoisomerism

atoms in molecules whose connectivity remains the same but their arrangement in space is different in each isomer. Geometric isomerism is sometimes considered synonymous with stereoisomerism, but is often used to describe just those stereoisomers that are not mirror-images of each other.

There are two forms of stereoisomerism:

• Geometric isomerism aka diastereomerism
• Optical isomerism aka enantiomerism