As expected from the high correlation between log k0 and VGoss (Figure ), the literature partition data shown in Figure also correlate with VGoss. Thus, the partitioning of anionic compounds in all systems considered appears to be primarily controlled by the size of the molecules. VGoss can equally well describe anion hydrophobicity, at least within the types of anionic PFAS and non-PFAS considered in this study. Since VGoss can be calculated from the molecular structure, it appears to be a more convenient descriptor than log k0. It is currently unknown to what extent VGoss might correlate with different partition coefficients if a wider range of compounds were considered. As an experimentally derived value, log k0 may have the advantage that it can at least reflect all relevant intermolecular interactions in the water phase, in contrast to VGoss, which only describes the difference in cavity formation. Data for more diverse structures, e.g., with branching, partial fluorination, and functional groups, are needed to evaluate the difference between k0 and VGoss.