The potential energy surface of nitrogen-rich ionic compound N7H2+ synthesized by N-5(+) and cis-N2H2 was investigated. The structures involved in the PES of N7H2+ were optimized using Hartree-Fork, MP2, hybrid functional theory, and CASSCF methods. The barrier height of synthesis pathway was predicted to be 46.8 kcal/mol corrected by ZPVE at the B3LYP/6-311++G** level. Such high barrier makes the synthesis reaction challenging, but raising the hope to achieve it by suitable catalyst. Electron density and molecular shape analysis were calculated to test the synthesis pathway as well. The result will provide suggestions for experimental synthesis of N7H2+ as a high energy-density material. (C) 2002 Elsevier Science B.V. All rights reserved.