Counting Sets of Constitutional and Chiral Isomers

Students in physical chemistry laboratories use group theory to count the number of unique positional isomers and chiral isomers of various compounds. Students use their knowledge of group theory and are introduced to Pólya’s counting theorem in order to generate a polynomial equation in which the coefficients are the number of isomers of a given type, and the number of enantiomer pairs. In addition, it affords an opportunity to introduce chemistry students to computer algebra software like Wolfram Mathematica. This laboratory exercise offers an excellent approach, for physical chemistry or computational chemistry courses, to expose students to the role of group theory in chemistry beyond the standard IR and Raman spectroscopy applications.