The set of symmetry operations (rotations, reflections, etc.) that can be applied to a molecule. This set forms the point group of the molecule. For an isolated molecule the Schoenflies system rather than the Hermann-Mauguin system is used to denote its symmetry. Molecular symmetry is analysed systematically using group theory. It is possible to make definite statements about certain properties of molecules, such as whether they can have an electric dipole moment or exhibit optical activity on the basis of symmetry.