5.2 Chirality
5.2 Chirality
Molecules which form a pair of enantiomers are necessarily chiral. A chiral molecule is related to its own mirror image in the way that your left hand is related to your right hand. All chiral molecules have at least one of the three kinds of chiral centers, the center of chirality, the axis of chirality or the plane of chirality. Molecules without any chiral center are achiral. There are many chiral substances around you, and you will find that the chirality quite often plays a definite role in relation to the property or function of the substance. Hands, gloves, and screws are familiar examples. The representative molecule with a center of chirality is a methane derivative, a sp3 hybridized carbon atom with four different ligands which can be represented as CXYZW (X ≠Y ≠ Z ≠ W). This type of carbon atom is referred to as asymmetric carbon atom. Asymmetric carbon atoms are sometimes indicated by * as superscript in the chemical formula.