There are molecular structures that have symmetry. Once certain transformation in three-dimensional space is carried out (symmetry operations), the molecules will look indistinguishable from its initial orientation. These operations may be performed along a line, a plane or a point (symmetry elements).

Reflection (σ) – Symmetric in the plane

Rotation (Cn) – Symmetric along an n-fold symmetry axis

Inversion (i) – Symmetric through the inversion center

Improper Rotation (Sn) – Symmetric through an improper axis ; Rotate 360/n degrees and reflect through the plane perpendicular to the axis

Symmetry of molecules is helpful in group theory and this has some applications in chemistry. Isn’t it interesting to see that even small particles like these have symmetry?


See the link below to see the animation of certain molecules: