Challenging the limits of the oxygen balance of a pyrazole ring

3,4,5-Trinitropyrazole was successfully functionalized with the trinitromethyl group to give 1-trinitromethyl-3,4,5-trinitropyrazole (3), which was structurally characterized by IR, NMR, elemental analysis, and single-crystal X-ray diffraction. Compound 3 exhibits a super-high density (2.006 g cm−3 at 170 K, 1.964 g cm−3 at 296 K), excellent oxygen balance (+18.1 %), and good thermal stability (160 ℃). With X-ray data and quantum computing, the intermolecular interactions of 3 was carefully studied to investigate its structure–property relationship. The high density, excellent oxygen balance, good thermal stability, along with its green feature (chloride free) make compound 3 a potential replacement for ammonium perchlorate (AP) and ammonium dinitramide (ADN) in solid propellants.