Racemic Mixture

Racemic Mixture

A (1:1) 50:50 mixture of two enantiomers. One enantiomer rotates light clockwise. The other rotates light the same amount counterclockwise. The rotations cancel. No overall rotation of light. A racemic mixture is optically inactive. Each individual molecule is chiral and is optically active. But because there are equal numbers of both enantiomers, the mixture is optically inactive

A racemic mixture is optically

inactive

Optically Active

An optically active molecule can rotate plane-polarized light. A molecule is usually optically active if it is chiral. Has no plane of symmetry. Is not superimposable on its mirror image. Most molecules with one chiral carbon are optically active.

Optically Inactive

A molecule is optically inactive if it is achiral. This usually happens if it has NO chiral carbons.