Symmetry in chemistry

Symmetry and chemistry have been in a fruitful interplay, initially in spectroscopy and crystallography, lately in more traditional domains of chemistry, such as reactivity and conformational analysis. A simple phenomenological approach suffices to get an idea about the symmetries of molecules whereas group theoretical approach greatly facilitates the understanding of molecular vibrations, electronic structure, and the mechanism of chemical reactions. In our discussion, the multi-level relationship between symmetry and chemistry is demonstrated by a sampler of examples, including the variations of symmetry of free molecules and molecular packing in crystals. Symmetry considerations continue to assist chemistry in systematizing and interpreting observations and also in discovering new reactions, molecules, and other materials.