Abstract
The available [Formula: see text] values for neutral organic compounds in aqueous solution can be fitted with useful precision by additivity schemes based on atomic, bond, or group contributions. For the set of 132 compounds these schemes require 11, 14, or 49 parameters and give weighted average deviations of 14, 9, or 6 J K−1 mol−1. For acyclic molecules the atomic contributions scheme permits chemically useful estimates of [Formula: see text] to be made for compounds of C, H, O, and N.