What is Molecular symmetry?
{{jargon|date=February 2024}} '''Molecular symmetry''' is a basic idea in [[chemistry]]. It describes the shapes of molecules in terms of the permutations of similar atoms in those molecules when they are transformed by the symmetry operations described below. It puts molecules into groups according to their symmetry. It can [[predict]] or explain many of a molecule's [[chemical property|chemical properties]].<ref>''Quantum Chemistry'', Third Edition John P. Lowe, Kirk Peterson {{ISBN|012457551X}}</ref><ref>''Physical Chemistry: A Molecular Approach'' by Donald A. McQuarrie, John D. Simon {{ISBN|0935702997}}</ref><ref>''The chemical bond'' 2nd Ed. J.N. Murrell, S.F.A. Kettle, J.M. Tedder {{ISBN|047190760X}}</ref><ref>''Physical Chemistry'' P. W. Atkins {{ISBN|0716728710}}</ref><ref>G. L. Miessler and D. A. Tarr “Inorganic Chemistry” 3rd Ed, Pearson/Prentice Hall publisher, {{ISBN|0-13-035471-6}}.</ref> Chemists study symmetry to explain how [[crystal]]s are made up and how [[chemical reaction|chemicals react]]. The molecular symmetry of the [[reactant]]s help predict how the product of the [[Chemical reaction|reaction]] is made up and the [[Activation energy|energy]] needed for the reaction. Molecular symmetry can be studied several different ways. [[Group theory]] is the most popular idea. Group theory is also useful in studying the symmetry of [[molecular orbital]]s. This is used in the [[Hückel method]], [[ligand field theory]], and the [[Woodward–Hoffmann rules]]. Another idea on a larger scale is the use of [[crystal system]]s to describe [[crystallography|crystallographic]] symmetry in bulk materials. Scientists find molecular symmetry by using [[X-ray crystallography]] and other forms of [[spectroscopy]]. [[Spectroscopic notation]] is based on facts taken from molecular symmetry. == Historical background == Physicist [[Hans Bethe]] used characters of [[point group operations]] in his study of [[ligand field theory]] in 1929. [[Eugene Wigner]] used group theory to explain the selection rules of [[atom