On structural interpretation of several distance related topological indices

We consider the role that individual bonds play in bond-additivities in ord er to better understand the structural basis of various topological indices . In particular we consider indices closely related to the Wiener index (W) and the distance matrix and search for optimal weights of terminal and int erior CC bonds in alkanes for a selection of physicochemical properties. It is interesting to note that different properties are associated with diffe rent relative roles of the exterior and the interior CC bonds.