Elements and Operations of Symmetry

Elements and operations of symmetry are interrelated terms, that is, a certain operation of symmetry is applied to a specific element, which results in the adoption of 

If rotation axis of symmetry (C exists, the initial configuration is recovered after rotation (operation of symmetry) at the angle of 2n n around a line crossing a molecule (element of symmetry). Linear molecules generate Coo-axis of symmetry automatically. 

The plane of symmetry (a) crosses a molecule. The reflection from the plane of symmetry (operation of symmetry) causes an exchange of the locations of the equivalent atoms. A planar molecule by itself is associated with the existence of plane of symmetry. 

Center of symmetry (i)— The initial configuration is recovered by reflection of a center, included in the molecular geometry. 

Mirror-rotation axis of symmetry (5 )— The rotation around a molecular C -axis at the angle of 2nln and the following reflection on a plane, which is perpendicular toward this axis (a composite operation of symmetry). 

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Symmetry elements provide the basis of symmetry operations. Thus, a molecule A is said to contain a given element of symmetry when the derived symmetry operation transforms A into a molecule to which it is superimposable. Elements and operations of symmetry are presented in Table 2, with the exception of the pseudooperation of identity which will not be considered. Table 2 shows that corresponding elements and operations of symmetry share the same symbol, and indeed these two terms lack independent meaning. 

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