Plane of Symmetry
An imaginary plane which bisects the molecule/species in two equal halves in such a way that each half of the molecule/species is the mirror image of the other half.The plane of symmetry or mirror plane always produces a mirror image geometry of the molecule . The mirror plane must include its center of geometry. Presence of mirror plane makes the molecule symmetrical and cause loss of chirality.
Example 1 :
Methene : It has plane of symmetry, hence it is optically inactive.
Example 2 :
Ethene : It has plane of symmetry, hence it is optically inactive.
Example 3 :
Methylene Chloride: CH
2Cl
2 It has plane of symmetry, hence it is optically inactive.
Example 4 :
2- Butene : It has plane of symmetry, hence it is optically inactive.
Example 5 :
Cyclo Butane : It has plane of symmetry, hence it is optically inactive.
Example 6 :
Allene : It has plane of symmetry, hence it is optically inactive.
Example 7 :
Lactic acid : It is chiral (optically active ). it has no plane of symmetry.