enantiomers
Enantiomers are optical isomers, which are mirror images of one another - roughly like the right and left glove. There may be only two enantiomers of a chemical. Two enantiomers twist polarized light in opposite directions, and some can form left- and right-handed crystalline forms. In addition, all physical properties and the vast majority of chemicals are almost identical for both enantiomers. There are only some differences in the energy of some chemical bonds in the order of 10-5 of their average energy, which have a minimal effect on the thermodynamic stability of the enantiomers. Basic methods to distinguish between two enantiomers or their solutions are based on interactions with other chiral compounds or with polarized electromagnetic radiation. With these methods, it is possible to determine not only the absolute configuration but also the enantiomeric excess. Whether a given compound has its enantiomer, or its mirror image is identical to itself, depends on the overall spatial structure of the compound.