The vertical electron detachment energies (VDE) of several NaL2- and MgL3- anions (where L= -ClO4, -ClO3, -ClO2, -ClO, -NO3, -PO3, -H2PO4, -HSO4, -HCO3, -SH) were calculated at the outer valence Green function level with the 6-311++G(3df,3pd) basis sets. It was shown that various acidic functional groups may act as ligands in superhalogen anions whose electronic stabilities always exceed 4eV. The largest values of the electron binding energies were found for the anions containing -ClO4 ligands (VDE=7.8-8.9 eV). The VDE dependencies on the origin of the ligand used (whether it is a functional group derived from strong or weak acid), chemical constitution of acidic functional groups and the electronegativity of the ligand's central atom were observed and discussed.