LiN5: A novel pentazolate salt with high nitrogen content

A high energy cyclo-pentazolate (cyclo-N5−) salt with 90.98 % nitrogen content, LiN5, was synthesized by a simple metathesis reaction of AgN5 and LiCl in deionized water. It was characterized by 15N nuclear magnetic resonance, infrared and Raman spectroscopy, elemental analysis, thermogravimetry-mass (TG-MS) spectrometry, and differential scanning calorimetry. Besides, its trihydrate (LiN5·3H2O) and anhydrous zeolitic architecture (LPF, lithium-pentazolate framework) structures were confirmed by single-crystal X-ray diffraction. LiN5 achieved stability in air and under ambient conditions. It starts to decompose when heated to 133 °C (onset) under Ar2 flow. Its relatively high density (1.75 g cm−3), impact and friction sensitivity (IS = 3 J; FS = 20 N), and calculated high heat of formation (3.44 kJ g−1), combined with its theorical superior detonation velocity and pressure (D = 11362 m s−1, P = 40.9 GPa), endow LiN5 with potential as an environmentally primary explosive.