Study on synthesis and reactivity of 5-nitro-2H-tetrazole and crystal structrue of some products

5-Nitro-2H-tetrazole (5) was prepared from 5-amino-1H-tetrazole (1) through diazotization and Sandmeyer reaction. 5 was then reacted with formaldehyde to form 5-nitro-2-hydroxymethyl-tetrazole (6), and 6 was reacted with concentrated HCl or HBr to form 5-chlorotetrazole (7) and 5-bromotetrazole (8), respectively. Their structures were characterized by MS, IR, ¹H NMR and ¹³C NMR techniques, and the crystal structures of 5-nitrotetrazole sodium salt (4), 5 and 6 were determined by X-ray single crystal diffraction analysis. 4 belongs to triclinic system with space group P-1; 5 and 6 belong to monoclinic system with space group P2₁, and the crystal parameters of 6 were a=0.66131(18) nm, b=0.54905(15) run, c=0.7566(2) nm, Z=2, V=0.27470(13) nm³, D_c= 1.754 g/cm₃, F(000)= 128, μ=0.160 mm^-1.