The adsorption energy provides information about which positions are preferentially populated. Consequently, adsorption of Mg was studied on the surfaces present according to the Wulff shape (Mg(0001), Mg(101 ! 0)A, Mg(101 ! 1)) as well as, for the sake of completeness, on Mg(101 ! 0)B. The respective adsorption energies (PBE/BEEF-vdW) and available literature data (PBE) are summarized in Table . In addition, a schematic representation of all adsorption sites studied is provided in SI Figure .