Crystal structure evolution of an energetic compound dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate induced by solvents.

Recently, energetic ionic salts have become a research hotspot due to their attractive properties, such as high density, high heat of formation, and environmental friendliness. Dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate (TKX-50) is a typical nitrogen-rich energetic ionic salt, which has broad application prospects. However, the research on the stability and crystal structure evolution of TKX-50 in different solvent systems is insufficient. Herein, we investigated the crystal structure transformations and searched for new solid forms of TKX-50 under different conditions via a solvent induction method. The phase composition of all screened samples was analyzed by powder or single-crystal X-ray diffraction. Three new solid forms of [NH 2 (CH 3 ) 2 + ][BTO - ], [NH 2 (CH 3 CH 2 ) 2 + ] 2 [BTO 2- ], [NHOH(CH 3 CCH 3 ) + ][BTO - ] H 2 O were obtained from DMAC, DEF and AC/MT, respectively. Furthermore, the energetic properties were evaluated through EXPLO5.