This paper explores whether principles obtained for the packing of solid macroscopic particles can be applied to the study of excess volumes of liquid mixtures. The approach is applied to mixtures of 'pure' hydrocarbons, i.e. containing only C- and H-atoms. In this new approach a set of equations was developed for the estimation of excess volumes of liquid hydrocarbon mixtures, which works better for mixtures of linear and cyclic hydrocarbons than existing estimation methods. An advantage of the new approach is that it reveals differences between mixtures of molecules with different steric character-istics, and shows that steric effects related to molecular shape and rigidity are necessary components of a fundamental understanding of liquid mixtures. (C) 2011 Published by Elsevier Ltd.