Nitrogen clusters have been intensively studied for their potential application as high-energy density materials, but a six-membered nitrogen ring (N-6) was not found to be stable and aromatic. To explore the possibility of inducing an aromatic N6 ring via cation-pi interaction, quantum chemistry calculations were performed on the systems of Ca2N6, CaN6, CaN62-, N-6, and N-6(4-) at the B3LYP/6-311+G* level. The optimized geometries reveal that the planar structure of the N-6 ring is stable only in the Ca2N6 complex. The computed NBO and CHelpG charges demonstrate that the planar N-6 moiety in the Ca2N6 complex is almost a 10 pi-electron system. The predicted nucleus-independent chemical shift (NICS) values demonstrate that the N-6 moiety is aromatic in comparison with the NICS values of benzene. The estimated enthalpy of formation for the Ca2N6 complex is 100.4 kcal/mol for the reaction of 2Ca and 3N(2). The binding energy between the Ca2+ cation and the N6(4-) moiety is -1928.8 kcal/ mol, with electrostatic interaction serving as the predominant component. When all the calculated results are taken into account, including the planar structure, 10 pi-electron system, identical bond length, and negative NICS value of the N6(4-) moiety in the Ca2N6 complex, it is deduced that the alkaline earth metal Ca is capable of inducing an aromatic N6 ring through the cation-pi interaction formed by electron transfer from the Ca atom to the N-6 ring.