S enantiomer

The S enantiomer refers to a specific form of a molecule that is a mirror image of its counterpart, the R enantiomer. These mirror-image molecules are called enantiomers. The "S" (from Latin *sinistra*, meaning left) designation indicates the spatial arrangement of atoms around a chiral center, which makes the molecule non-superimposable on its mirror image. Enantiomers can have different biological activities, so distinguishing between S and R forms is important in chemistry and medicine. Essentially, the S enantiomer is the "left-handed" version of a chiral molecule, with unique three-dimensional properties.