A procedure is developed and applied to characterize the global shape of the hydrogen-bonded networks formed in solvent and solute-solven t clusters. The methodology combines elements of geometry and topology of molecular chains, and it provides a description of the compactness and complexity of the entanglements formed by the network of hydrogen bonds between solute and solvent molecules. This approach complements others in the literature, where the hydrogen bonding is described in terms of the spatial distribution of bonds, their energetics and lifetimes, or the length hydrogen-bonded walks in space. The results of the present technique do not depend too strongly on the details of the molecular geometry. Therefore, one can assess the extent to which large-scale architecture is modified by rearrangements in the nuclear configuration, information which is important in molecular dyna:mics when estimating the persistence of essential structural features along dynamic trajectories. In this article we discuss the methodology and illustrate its application to the study of water clusters and solvated clusters of acetic acid. Expected qualitative features in the change of shape descriptors in actual reorganizations of hydrogen-bonding patterns are discussed brielly. 0 1994 by John Wiley & Sons, Inc. 4), it is only recently that the fine details of the he development of a reliable microscopic model of solvation processes is one of the challenges of modern physical chemistry and biophysics. 1-3 Computer simulations of molecular dy-T structure and dynamics of various hydrogen-