Salts of 1H-Tetrazole - Synthesis, characterization and properties

The most facile route for the formation of 1H-Tetrazole (1, TZ) is the reaction of sodium azide with ammonium chloride and orthoethyl formate in glacial acetic acid. 1 was deprotonated using alkali hydroxides and carbonates yielding the corresponding metal salts LiTZ (4), NaTZ center dot H2O (5), KTZ (6), RbTZ (7) and CsTZ (8). The nitrogen rich salts NH(4)TZ center dot H2O (2) and N(2)H(5)TZ (3) were synthesized by the reaction of 1H-tetrazole with aqueous NH3 and N2H4 Solutions, respectively. In addition, Sr(TZ)(2)center dot 5H(2)O (9) was obtained by deprotonation of 1 using Sr(OH)(2)center dot 8H(2)O and its use as possible energetic ingredient in modern pyrotechnic compositions as a red component was investigated. All compounds were characterized using vibrational (1R and Raman) spcctroscopy multinuclear (H-1, 7Li, C-13, N-14, N-15) NMR spectroscopy and elemental analysis. The structures in the crystalline state of compounds 2, 3, 4, 5, 6, 7 8 and 9 were determined using low temperature X-ray diffraction and a detailed description is given in this work. The physico-chemical properties Of all Compounds were investigated using DSC (differential scanning calorimetry) and the heats of formation Were calculated using heats of combustion obtained by bomb calorimetry. Since tetrazoles often are energetic materials. the sensitivities of compounds 1-9 were tested Using the BAM drophammer and friction tester. Crystal Data: 2: monoclinic, P2(1)/n, a = 7.211(1), b = 4.0108(8), c = 17.991(4) angstrom, beta = 91.97(3)degrees, V = 520.0(2) angstrom(3), Z = 4, rho = 1.343 g cm(-3); 3: orthorhombic, Ccca, a = 6.763(l), b = 17.7510(4), c = 16.3160(8) angstrom, V = 1958.7(3) angstrom(3), Z = 16, rho = 1.385 g cm(-3); 4: orthorhombic, C222(1), a = 13.499(2), b = 14.389(3), c = 14.125(3) angstrom, V = 2743.6(9) angstrom(3), Z = 8, rho = 1.472 g cm(-3); 5: orthorhombic, Pmma, a = 6.400(2) b = 5.837(1), c = 5.608(2) angstrom, V = 209.51(9) angstrom(3) Z = 2 rho = 1.745 g cm(-3); 6: hexagonal, P (6) over bar, a = 14.0037(2), b = 14.0037(2), c = 10.7285(2) angstrom, V = 1822.03(5) angstrom(3), Z = 6, rho = 1.774 g cm(-3); 7: hexagonal, P63/m, a = 8.260(2), b = 8.260(2), c = 11.009(3) angstrom, V = 650.5(3) angstrom(3), Z = 6, rho = 2.367 g cm(-3); 8: orthorhombic, Pbca, a = 7.3406(8), b = 9.610(1), c = 12.199(1) angstrom, V = 860.5(2) angstrom(3), Z = 8, rho = 3.118 g cm(-3); 9: orthorhombic, Pnnm, a = 11.314(2), b = 13.876(3), c = 7.121(1) angstrom, V = 1117.9(4) angstrom(3), Z = 2, rho = 1.877 g cm(-3).