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Preparation, Crystal Structure, Thermal Decomposition, and Explosive Properties of a Novel Energetic Compound [Zn(N2H4)2(N3)2]n: A New High-Nitrogen Material (N = 65.60 %)



A new multi-ligand coordination polymer of zinc(II) hydrazine azide, [Zn(N2H4)2(N3)2]n, was synthesized and characterized by elemental analysis and FT-IR spectrum. Its crystal structure was determined by single crystal X-ray diffraction analysis: triclinic, space group Pequation image, a = 0.4121(1) nm, b = 0.6281(1) nm, c = 0.7072(2) nm, α = 68.443(6)°, β = 89.360(11)°, γ = 89.197(9)°,V = 0.1702(1) nm3, Dc = 2.083 g·cm–3, Z = 1, R1 = 0.0316, wR2 [I > 2σ(I)] = 0.0780 and S = 0.998. The ZnII ion is hexacoordinated with two azido ligands by μ1-azido bridges and four hydrazine molecules, which serve as bidentate ligands through the nitrogen atoms. The thermal decomposition mechanism of the title complex was studied by differential scanning calorimetry (DSC) and thermogravimetry-derivative thermogravimetry (TG-DTG) techniques. Under nitrogen atmosphere with a heating rate of 20 K·min–1, the thermal decomposition of the complex contained one main endothermic process and two main successive exothermic processes between 474 K and 648 K in the DSC curve. Its combustion heat was measured by oxygen bomb calorimetry. The non-isothermal kinetics parameters were calculated by the Kissinger’s method, Ozawa-Doyle’s method, pervasive integral method, and differential method, respectively. The sensitivity properties of [Zn(N2H4)2(N3)2]n were also determined with standard methods, which was very sensitive to external stimulus.