Van der waals volumes and radii

Abstract

Intermolecular van der Waals radii of the nonmetallic elements have been assembled into a list of "recommended" values for volume calculations. These values have been arrived at by selecting from the most reliable X-ray diffraction data those which could be reconciled with crystal density at 0°K. (to give reasonable packing density), gas kinetic collision cross section, critical density, and liquid state properties. A qualitative understanding of the nature of van der Waals radii is provided by correlation with the de Broglie wave length of the outermost valence electron. Tentative values for the van der Waals radii of metallic elements - in metal organic compounds - are proposed. The paper concludes with a list of increments for the volume of molecules impenetrable to thermal collision, the so-called van der Waals volume, and of the corresponding increments in area per molecule.