Symmetry is a property of molecules having more than one atom of the same kind, with equal bond lengths and/or bond angles. As like the high symmetry of the SF6 molecule (Fig. 1. arises from the six equal S-F bonds disposed at angles of 90° to each other. In order to build the notion more precise we use the idea of a symmetry operation. For example rotating SF6 by 90° about an appropriate axis, it appears indistinguishable after the rotation. The axis concerned is known as the symmetry element. Rotations which do not leave the molecule looking the similar are not symmetry operations.