Optical Isomerism
Stereoisomerism in which molecules are non-superimposable mirror images and rotate plane-polarised light in opposite directions.
Unit
degrees
In depth
Optical isomers share every scalar physical property — melting point, density, solubility — and differ only in their interaction with other chiral entities. Since biological receptors are chiral, the two forms of a drug can have utterly different effects.
Examples in the real world
The two forms of limonene smelling of orange and of lemon; thalidomide's tragically different enantiomers.