An Exploring Study On Metastable Polynitrogen Cluster Compounds

The properties, main uses and research direction of high energy density material (HEDM) were summarized in this paper. Several public HEDMs were also mentioned. The present research situation of polynitrogen atomic cluster was also stated. An all-nitrogen molecule Nx can undergo the reaction ( )N x→x 2 N2, a reaction that can be exothermic by 50 kcal?mol-1 or more per nitrogen atom. So it could become potential high performance ammunitions and the spacecraft fuel. However, it is difficult to synthesize all-nitrogen molecules under normal conditions, because it is not stable and can explode easily.Gas reaction method, liquid reaction method and low temperature reaction method were performed in this study to find the producing possibility and conditions and examination methods of polynitrogen atomic clusters. Using direct current arc discharge method and ammonia and hydrogen with volume ratio of 1:10 as reactants, black solid which it has the obvious crystal lattice stripe was obtained. The level spacing approximately is 0.25nm. The binding energy of the product is 397.53, 400.13 and 401.91eV respectively and their peak area proportion is 10.71%, 49.19% and 40.10% respectively.Polynitrogen atomic cluster have been detected from the product obtained by electrolyzing solution of ammonia and oxydol and ommonium chloride and sodium azide using copper, platinum and stainless steel as electrodes. Polynitrogen atomic cluster have been also be produced by the reaction of nitrogen trichloride with sodium azide at low temperature.A theoretical conclution on the optimized structures, energies and relative stabilities of sodium nitrides of NxNa (x=6, 8, 10, 12, 14) was carried out using density functional theory (DFT) methods at B3LYP level. The total energies E, molar heat capacity at constant volume Cv, entropies S, Zero-point vibrational energies ZPEs and enthalpies of formation ?H fo increase when the number of N atoms increases. The molecule orbital analyses were also performed. It was found that N10Na was most stable and N6Na was second stable among NxNa (x=6, 8, 10, 12, 14).