In the case of As(III)-PhosO complexes, electrostatic interactions (EELEC) mainly govern the inner-sphere surface complexation, overcoming 58% of the total stabilizing energy. Then, permanent Coulombic electrostatic attraction is the main driving force determining the stability of As(III)-PhosO complexes in solution. In addition, we found stabilization gained by electrostatic interactions (EELEC) enhances in up to two orders of magnitude upon adsorption on phosphorene oxide compared to the unoxidized material. For instance, the As(III)-Phos and As(III)-PhosO complexes are stabilized in EELEC-1.7 and EELEC-3.5 eV by electrostatic interactions, respectively (Table ), corresponding to single stabilizing contributions of 58 and 60%, respectively (Fig. ). Note also that the relative single percentage contributions (Φi) are similar between pristine and oxidized adsorbents (Fig. ), denoting that adsorption on both materials is governed by similar driving forces.