MCl2-, M(NO3)(2)(-), and (Cl-M-NO3)(-) (M = Li, Na, K) species are systematically investigated using the density functional theory. In all the cases studied, the vertical detachment energies (VDEs) exceed the electron affinity of chlorine atom, leading to the conclusion that MCl2-, M(NO3)(2)(-) and (Cl-M-NO3)(-) are superhalogens. The VDEs of (Cl-M-NO3)(-) are between that of MCl2- and M(NO3)(2)(-), showing that replacing one ligand with a larger electronegative ligand leads to the higher VDE. Superhalogens with suitable VDEs can be built by using different ligands. (C) 2016 Elsevier B.V. All rights reserved.