Stereoisomers are isomers that differ in the spatial arrangement of atoms, rather than the order of atomic connectivity. One of the most interesting types of isomer is mirror-image stereoisomers, a no...Stereoisomers are isomers that differ in the spatial arrangement of atoms, rather than the order of atomic connectivity. One of the most interesting types of isomer is mirror-image stereoisomers, a non-superimposable set of two molecules that are mirror images of one another. The word "chiral" was derived from the Greek word for hand, because our hands are good example of chirality since they are non-superimposable mirror images of each other.