ABSTRACT
Organic compounds that have the same chemical formula but are attached to one another in different ways are called isomers. Isomers that have the same chemical formula and are attached to one another in same way but whose orientation to one another differ are called stereoisomers. There are several different types of isomers that are encountered in organic chemistry. In addition to having different arrangements of atoms, certain organic compounds exhibit a unique property of rotating plane-polarized light. Molecules that are not superimposable on their mirror images are chiral. Chiral molecules exist as enantiomers but achiral molecules cannot exist as enantiomers. Diastereomers are stereoisomers that are not mirror images of each other. Diastereomers have different physical properties. A mixture of equal parts of enantiomers is called a racemic mixture. A racemic mixture contains equal parts of D and L components and therefore, the mixture is optically inactive.
