Stereoisomers

They are molecules in which the atoms are joined in the same order, but the positions are different in space.

Isomers which have their atoms connected in the same sequence but differ in the way the atoms are oriented in space, the difference between two stereoisomers lies only in the three dimensional arrangement of atoms. Stereoisomers can be classed as cis-trans isomers or optical isomers.

Optical isomers

Optical isomers are mirror images of one another. Just as a right-handed glove cannot be superimposed on a left-handed glove, optical isomers cannot be superimposed on one another.