Synthesis and structure analysis of diammonium 3,5-dinitro-1,2,4- cyclopentanetrione

A new energetic ionic compound, diammonium 3,5-dinitro-1,2,4- cyclopentanetrione (DDCP), has been synthesized. It has been characterized by elemental analysis, IR, and single-crystal X-ray diffraction. The compound crystallizes in triclinic system, space group P1, a=4.485(1) Å, b=7.527(1) Å, c=13.367(1) Å, α=94.15(1)°, β=92.73(1)°, γ=101.75(1)°, V=439.72(11) ų, Z=2, and D _calc=1.784 Mg m^-3; R=0.0331, R _w=0.0892 for 1643 reflections with I>2σ(I). The entities of two ammonium cations and 3,5-dinitro-1,2,4-cyclopentanetrione anions are held by electrostatic forces and intermolecular hydrogen bonds. The bivalent anion exists as all kinds of resonance structures, which is in favor of stability of the anion. The thermal decomposition of title compound is studied by using DSC and TG-DTG techniques. The results show that the title compound has a higher enthalpy change and can evolve abundant gas products.