Toward cracking the problem of understanding, characterizing, and predicting “solvent-effect” while the world awaits an effective explicit solvent model, we introduce and justify herein a novel set of atomic radii to be used within the most commonly used continuum reaction field, the polarizable continuum model (PCM). The radial values emerge from a quantitative description of the elemental electronic density distribution and are shown to be accurate in such a self-consistent reaction field (SCRF); labeled accordingly as isodensity-based SCRF (IDSCRF) radii. Transition row elements with dynamic oxidation states are addressed through an averaging of the electronic properties from all states in the determination of their effective radii. All results for nonmetal elements have been verified with Guthrie's SAMPLE1 test set and are in quantitative agreement with experimental values from the literature and self-consistent isodensity polarizable continuum model (SCIPCM) calculations. For the compounds with transition metal elements, our IDSCRF results have been verified with SCIPCM results as there are rarely experimental results available. Finally, explicit solvent particles “solvating” Pd- and Ni-containing homogeneous catalysts are also shown to be in close agreement with the IDSCRF radii calculations. © 2012 Wiley Periodicals, Inc.