The structures and stability of nitrogen cluster N-10 were studied using DFT and MP2 methods. Eleven minima were optimized and characterized by both B3LYP/6-31G* and MP2/6-31G* harmonic vibrational frequency calculations. The stability was studied in terms of the barriers of isomerization and dissociation reactions on the potential energy surface (PES) of nitrogen cluster N10. The low barriers show that nitrogen clusters N-10 studied in this paper are not stable enough to be used as high-energy density-materials (HEDMs). (C) 2004 Elsevier B.V. All rights reserved.