Q. Explain about Optical Isomerism?

Optical Isomerism: -Two isomers which have almost identical physical and chemical properties like mp. B p. density. Colour etc.. But differ in the way they rotate the plane-polarised light are called optical isomers. Such optically active compounds exist in pairs and are known as stereoisomers or enantiomers. These isomers are    non-super imposable mirror images of each other. Hence any molecule which contains either a-centre of symmetry or a plane of symmetry will not show optical isomerism.

Optical isomerism is rarely observed in square planar complexes. Tetrahedral complexes of the type [M(AB)₂] do give optical isomers as shown in Fig, especially where  /  M = Be, B etc.

However optical isomerism very common with octahedral complexes of the type!  M (AA)₃. M(AA)₂ab, M(AA)a₂,b₂. M(AA)(BB)a₂ etc. A few typical examples.