A Regularity for the Boiling Points of Alkanes and Its Mathematical Modeling

In a series of isomeric monomethyl alkanes the boiling points alternately decrease and increase as the methyl group is displaced along the carbon-atom chain. Hosoya's topological index can well reproduce this regularity. Other topological indices (the polarity numbers, Wiener's and the connectivity index) are less successful in this respect. Some further regularities in the dependence of the boiling points on molecular structure are suggested.