Most of the dependencies on the orbital energy are exponential, in some cases they are close to the linear type, as the theoretical estimates suggest (Figure ). Linear dependencies are also reported for the adsorption of neutral molecules on metal oxides in refs. Volcano-shaped dependencies are observed for the anions on Al 2 O 3 (Figure ) and cations on graphene (Figure ), which is also in agreement with the theory. The splitting of the dependencies for E ads into two branches is observed only for the anions on graphene (Figure ). There is a split in all the z 0 anion dependencies on ε HOMO and ε LUMO . One cause of the division of the anions into two groups may be the presence of several MOs with the same energy (Ta-ble S6.1). This effect will be discussed in more detail in the next paragraph.