I know that enantiomers are mirror images which are not superimposable on each other.

What about mirror images which are superimposable? Are they necessarily the same molecule? Is there a particular term for them?

  • 7
    $\begingroup$ Well, if you can superimpose them then they are identical. What is there to ask about? $\endgroup$ – Mithoron Sep 23 '16 at 23:15
  • $\begingroup$ Mirror images are mirror images. I suspect that what you mean is ‘what is a molecule called, which is superimposable on its mirror image?’ $\endgroup$ – Jan Sep 23 '16 at 23:31

If two molecules are superimposable, they would by definition be the exact same molecule. There is no chemical test you could perform to differentiate them. This is true for all achiral compounds.

The most interesting case of this would be a class of molecules called meso compounds. They contain multiple stereogenic centers, but due to an internal plane of symmetry (or certain other symmetry elements), reflection of these molecules across a mirror plane results in superposable mirror images.


Not the answer you're looking for? Browse other questions tagged or ask your own question.