Symmetry Planes and Reflections

A symmetry plane must pass through a body, that is, the plane cannot be completely outside of the body. The conditions which must be fulfilled in order that a given plane be a symmetry plane can be stated as follows. Let 

TABLE 3.1 The Four Kinds of Symmetry Elements and Operations Required in Specifying Molecular Symmetry 

Center, of symmetry or center of inversion Inversion of all atoms through the center 

Proper axis One or more rotations about the axis 

Improper axis One or more repetitions of the sequence rotation followed by reflection in a plane L to the rotation axis 

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