Figure 2.11. Rotation of an Achiral MoleculeEnantiomers
Enantiomers (nonsuperimposable mirror images) have the same connectivity but opposite
configurations at every chiral center in the molecule. Enantiomers have identical physical and
chemical properties with two notable exceptions: optical activity and reactions in chiral
environments.
KEY CONCEPT
Enantiomers have nearly identical physical properties and chemical properties, but they
rotate plane-polarized light in opposite directions and react differently in chiral
environments.A compound is optically active if it has the ability to rotate plane-polarized light. Ordinary light is
unpolarized, which means that it consists of waves vibrating in all possible planes perpendicular to
its direction of propagation. A polarizer allows light waves oscillating only in a particular direction to
pass through, producing plane-polarized light, as shown in Figure 2.12.