Point Group Symmetry

The symmetry of a molecule is determined by the existence of symmetry operations performed with respect to symmetry elements. A symmetry element is a line, a plane or a point in or through an object, about which a rotation or reflection leaves the object in an orientation indistinguishable from the original. For more click here or here.

Courtesy: Prof. Reusch, http://www2.chemistry.msu.edu  and
                  Margaret Kastner, Timathy Medlock and Kristy Brown