Periodic DFT method has been firstly used to calculate the bulk structure, electronic structure, electrical transferring and thermodynamic properties of crystalline 5-azido-1H-tetrazole (HCN₇) and its four different salts. The anion CN₇(-) was included in all of the salts such as ammonium 5-azidotetrazolate ([NH₄](+)[CN₇](-)), hydrazinium 5-azidotetrazolate ([N₂H₅](+)[CN₇](-)), guanidinium 5-azidotetrazolate ([CH₆N₃](+)[CN₇](-) · H₂O) and 1-aminoguanidinium 5- azidotetrazolate ([CH₇N₄](+)[CN₇](-)). The simulation is in reasonable agreement with the experimental results. It is found the salts of HCN₇ are more stable than itself because the band gap of the salts is larger. The density of state shows the p states of them (including HCN₇ and its four salts) have played a very significant role in the reaction.