How do you tell the difference between enantiomers and diasteromers?

Question

Nolan Allen · Accepted Answer

A pair of enantiomers are non-suposable MIRROR images. Diastereomers are geometric isomers that are not mirror images.

Cis - trans isomerism is diastereomeric by this definition. For cis -2-butene, the connectivity is precisely the same as for trans -2-butene: #C_1# is connected to #C_2# is connected to #C_3# etc. Nevertheless the spatial geometry of each isomer is distinct. Of course I could propose diastereomers that have 2 or more chiral centres (i.e. #R,S# versus #R,R# etc.; these are diastereomeric but are clearly NOT enantiomeric), but this is much more difficult to represent meaningfully (good thing that I didn't split that last infinitive!).

Elias Aguila · Answer

undefined Enantiomers are a pair of molecules that are non-superimposable mirror images of each other, meaning they have the same connectivity of atoms but differ in their spatial arrangement. Diastereomers, on the other hand, are stereoisomers that are not mirror images of each other and have different spatial arrangements at one or more stereocenters. In summary, enantiomers are mirror images of each other, while diastereomers are not.