Enantiomer
One of a pair of stereoisomers that are non-superimposable mirror images of each other.
Formula / equation
(+) and (−), or R and S
Unit
degrees
In depth
Enantiomers rotate polarised light by equal amounts in opposite directions and are identical in every other physical property, which makes them very difficult to separate. Resolution requires reaction with a chiral agent or chromatography on a chiral stationary phase.
Examples in the real world
D- and L-glucose; only the S enantiomer of naproxen is an anti-inflammatory, the R form damages the liver.