Abstract:In order to study the formation rule of hydrogen bonds in pentazole non-metal salts and its influence on stability, the Reduced Density Gradient (RDG) theoretical analysis method was used. The hydrogen bonding interactions of a single N5- anion and its surrounding cations in the structure were investigated. The hydrogen bond length was read from the single crystal structure of each compound, and the strength was obtained from the RDG analysis. Results show that N5- anion can form two types of hydrogen bonds, N—H…N and O—H…N, with N—H and O—H proton donors with electro positivity. O—H…N hydrogen bonds are stronger, while N—H…N hydrogen bonds are weaker. There are two factors influencing the stability of N5- anion, one is the structure symmetry of N5- anion, and the other is the graphene-like structure that forms a crystal plane layer. Under the interaction of hydrogen bonding, N5- anion maintain good structural symmetry (biguanidinium pentazolate salt, 10) and graphene-like structure (3,6,7-triamino-7H-[1,2,4]triazolo[4,3-b] [1,2,4]triazol-2-ium pentazolate salt, 12), which can significantly improve the stability and bring the decomposition temperature up to 124.8 and 120.9 ℃. On the contrary, if the hydrogen bonding causes serious deformation of N5- anion structure, which leads to the loss of symmetry and fails to provide planar stacking (oxalohydrazinium pentazolate salt, 3 and 4,4’,5,5′-tetraamino-3,3′-bi-1,2,4-triazol-2-ium pentazolate salt, 4), the stability of the N5- anion will decrease significantly, and the decomposition temperature is only 95 oC.