What is the difference between an enantiomer and a diastereomer?

1 Answer
Nov 25, 2015

An enantiomer is the non-superimposable mirror image of another. A diastereomer can have one or more (but not all) different stereocenters.

From this definition, we can see that the "not all different stereocenters" specification is the differentiating factor between a diastereomer and an enantiomer. It's easier to see with a picture.

  • D-threose and L-threose are enantiomers since they are non-superimposable and are reflections of each other.

  • D-erythrose and L-erythrose simply have their #alpha# carbon's #"OH"# and #"H"# nudged to switch the configuration, relative to D-threose and L-threose, respectively.