Optical isomerism

• Optical isomerism is a form of stereoisomerism. Optical isomers (also called enantiomers) are non-superimposable mirror images of each other.
• Molecules with four different groups bonded to one carbon atom have two non superimposable mirror images of each other.

  This carbon atom is known as the chiral centre, and it is the chiral centre that leads to chirality in molecules
• Optical isomers are called optical because of how they interact with polarised light
• Light has a property called polarisation. If light is plane polarised, this means that all of its light waves have the same polarisation
• Enantiomers will rotate plane-polarised light in different directions: clockwise and anticlockwise
• Some chemical reactions can produce a specific enantiomer, whereas some produce equal amount. An equal mixture of enantiomers is called a racemate/racemic mixture.

  These mixture are optically inactive because the opposite optical activities of each enantiomer will cancel each other out.