Yet another definition for the vdW radius was proposed by Bader, based on the average distance from the nucleus, where the electron density falls to 0.001 electrons per Bohr. This particular value was chosen to correlate well with crystallographic vdW radii for neutral and ionic atoms. An alternative approach consists of analyzing the free-atom electron densities compared to the electron density of corresponding noble-gas atom at a distance of their vdW radii from the nuclei. This approach has been employed in the Tkatchenko-Scheffler method to obtain the reference atomic vdW radii. More specifically, this methodology consists of four steps: i) Calculate the electronic density of the noble gas atom at a given level of theory, ii) ) Find the value of the electronic density at the distance of the noble gas vdW radius with respect to its nuclei. iii) For any atom of the same row of the periodic table, calculate the electronic density, iv) find the value of the radial distance corresponding to the same value of the electronic density obtained for the noble gas atom; this distance corresponds to the vdW radius of the atom. In the Supporting Information, we illustrate the above procedure, and we compared several quantum chemistry methods and basis sets for the helium atom, showing no remarkable difference, where the highest level is FCI/CBS with a density contour of 0.0008 a.u. at distance from the nuclei equal to its R vdW of 2.65 Bohr. Boyd showed that below an electron density of 0.001 au, the relative radii of atoms are nearly invariant to small changes in the density cutoff, and still satisfy the periodic trends in a given period and group of the periodic table. Therefore, it is a suitable option to choose the distance at the R vdW of helium defined by Batsanov, which is already consistent for the whole periodic table and not only within the first period, leading to a value of 3.10 Bohr for the free hydrogen atom. A slightly more exotic approach for estimating interacting (non-covalent) atomic radii is based on the equilibrium distance of diatomic anions bound by positrons. These are systems in which a positron plays a major role in neutralizing and bonding two otherwise repulsive anionic atoms, forming a stable compound at a specific internuclear distance. One common feature in the studied positron-bonded systems is the small change in the electronic density distribution and the lack of electronic covalent bonds between atoms. For example, two or one positrons can bind together two hydrogen anions in 2 e + [H -H -] or e + [H -H -], with an equilibrium distance of 6.00 and 6.36 Bohr, respectively. Based on this finding, we can propose an estimation of the hydrogen anionic radius, and by extension, hydrogen atom vdW radius, due to the similarity between vdW radii of neutral atoms and their anionic radii as initially observed by Pauling. Therefore, the positron orbital creates an attractive force between two repulsive closed-shell anions until reaching the inter-penetrability limit of the electronic clouds. This is not unlike vdW systems where the Pauli repulsion balances the attraction forces between the non-covalently bonded closed-shell atoms. Hence, we suggest an estimate of 3.00 to 3.18 Bohr for the vdW radius of free hydrogen atom from the hydrogen anion dimer bonded by one or two positrons.