Preparation,crystal structure,thermal decomposition and explosive properties of the novel compound [Mg(H 2 O) 6 ](ATZ) 2 (PA) 2 (ATZ = 4-Amino-1,2,4-triazole and PA = Picrate)

Abstract

The novel coordination compound of [Mg(H₂O)₆](ATZ)₂(PA)₂ (1) was synthesized by using 4-amino-1,2,4-triazole (ATZ) and picrate (PA) and characterized by elemental analysis and FT–IR spectrum. The crystal structure was determined by X-ray single crystal diffraction and the crystallographic data showed the crystal belong to triclinic, pertains to P–1 space group, α = 6.980(4)Å, b = 7.047(4)Å, c = 15.603(10)Å, α = 83.84(2)°, β = 81.99(1)° and γ = 82.66(2)°. The Mg(II) ion is six–coordinated with six oxygen atoms from crystal water molecules and exhibits distorted–octahedral configuration. Furthermore, thermal analysis indicated a melting point peak at 133.5°C, and then three main exothermic processes occurred as shown in the differential scanning calorimeter (DSC) curve corresponding to thermogravimetry–derivative thermogravimetry (TG–DTG) curves. The kinetic parameters of the first exothermic process were studied by using Kissinger's method and Ozawa's method. The enthalpy of formation, critical temperature of thermal explosion, entropy of activation (ΔS^≠), enthalpy of activation (ΔH^≠), and free energy of activation (ΔG^≠) were calculated and obtained as −3172.15 kJ·mol⁻¹, 506.92 K, −160.36 kJ·mol⁻¹, 134.91 J·(·Kmol)⁻¹ and 213.73 kJ·mol⁻¹, respectively. The flame and impact sensitivities measuring results showed the 50% firing heights were 9.6 cm and 78.5 cm ( = 38.5 J), respectively.