3,6-Diazido-1,2,4,5-tetrazine (DAT) has been synthesized from 3,6-bis(3,5-dimethylpyrazol-l- yl)-1,2,4,5-tetrazine by hydrazinolysis and diazotization. The molecular geometries, infrared vibrational spectra, and thermodynamic properties of DAT were calculated using the density functional theory (DFT) method at the B3LYP/6-31G* level. The investigation into simulation and experiment of IR spectra indicates that there exists no azido-tetrazole tautomerism in solid DAT. The thermodynamic parameters including heat capacities, entropies and enthalpies were calculated according to IR spectra, and also the polynomial functions between thermodynamic parameters and temperature were determined. The accurate heat of formation 1088 kJ•mol^－1 of DAT in gas phase was obtained via designed isodesmic reaction in which the tetrazine ring and the azide group have been kept. The data obtained from the present study show a satisfactory detonation performance, with detonation velocity D of 8.45 km•s^－1 and detonation pressure P of 31.3 GPa, both of which are higher than those of TNT and HMX counterparts.

Key words: tetrazine, azide group, quantum chemical calculation, heat of formation