Consistent van der Waals Radii for the Whole Main Group

Abstract

Atomic radii are not precisely defined but are nevertheless widely used parameters in modeling and understanding molecular structure and interactions. The van der Waals radii determined by Bondi from molecular crystals and noble gas crystals are the most widely used values, but Bondi recommended radius values for only 28 of the 44 main-group elements in the periodic table. In the present article we present atomic radii for the other 16; these new radii were determined in a way designed to be compatible with Bondi’s scale. The method chosen is a set of two-parameter correlations of Bondi’s radii with repulsive-wall distances calculated by relativistic coupled-cluster electronic structure calculations. The newly determined radii (in Å) are Be, 1.53; B, 1.92; Al, 1.84; Ca, 2.31; Ge, 2.11; Rb, 3.03; Sr, 2.50; Sb, 2.06; Cs, 3.43; Ba, 2.68; Bi, 2.07; Po, 1.97; At, 2.02; Rn, 2.20; Fr, 3.48; and Ra, 2.83.

New phosphorus containing bis-sulfone ligands

“…The O1-P1 distance is of 3.195(1) Å, the O3-P1 is 2.924(1) Å, values between the sum of the covalent radii (1.73 Å) [26] and the sum of the van der Waals radii (3.38 Å). [27,28] The P-O5 and P-O6 distances are in the range of values found in the literature for P=O bonds. [35] Compound 4 is stable in the presence of moisture and oxygen.…”

“…[20,25] The tolyl groups are situated on opposite sides of the central aromatic ring; the S=O bonds are close to values observed in the case of the previously reported metallylenes with bis-sulfone ligands. [17][18][19] The O1-P1 distance in the dichlorophosphine 2 is of 2.754(3) Å, value between the sum of the covalent radii (1.73 Å) [26] and the sum of the van der Waals radii (3.38 Å), [27,28] while the O3-P1 distance of 3.367(3) Å is almost equal to the sum of the van der Waals radii (3.38 Å). [27,28] The orientation of the sulfonyl groups (the O1, O3) and the phosphorus atom does not make possible an interaction, moreover, in the case of the phosphorus(III) atom, the presence of the lone pair of electron could lead to repulsions with the lone pair of electron on the oxygen atom.…”

Four-Component Relativistic Calculations in Solution with the Polarizable Continuum Model of Solvation: Theory, Implementation, and Application to the Group 16 Dihydrides H2X (X = O, S, Se, Te, Po)

“…The cavities were generated using the Bondi-Mantina set of van der Waals radii 111 . The radii used 1.20 radii were then multiplied by a scaling factor of 1.2 as usual in the application of the PCM 112 .…”

Equation of motion for the solvent polarization apparent charges in the polarizable continuum model: Application to time-dependent CI

“…The molecular-shaped cavity is generated using the GePol algorithm 43 using three spheres centered at atomic position with radii equal to the atomic van der Waals radii reported in ref. 44 with a locally modified version of the Gaussian G09 (A02) package. 45 In the numerical applications of the EOM-PCM/TD-CIS method we have limited the many-electron basis set to the Hartree-Fock ground state and to the lowest 5 CIS excited states determined in the presence of the PCM frozen reaction field.…”