Tracing environment effects that influence the stability of anion–anion complexes: The case of phosphate–phosphate interactions

The effect of the environment on the stability of the (H3PO4)2, ( H 2 PO 4 - ) 2 and ( HPO 4 2 - ) 2 hydrogen bonded dimers has been explored by the topological analyses of the theoretical electron density and the electrostatic potential. The environment has little effect on the hydrogen-bonding interaction, while it induces a significant one on the Coulombic component of the dimer. The interaction energy is represented in terms of hydrogen-bond and non-hydrogen-bond contributions, being only the latter affected by the charge or the environment. While the non-hydrogen bond contribution dominates the interaction energy in the gas phase, it becomes balanced in a polarizable environment.