B(N 5 ) 3 : Stabilized Boron Pentazolates with Promising Performance as High–Energy–Density Material

In this work, we identify two high–pressure boron pentazolate phases, P2 1 −B(N 5 ) 3 and P1−B(N 5 ) 3 , via ab initio evolutionary searches. These phases contain cyclo-N 5 − units arranged into distinct one-dimensional and layered B–N frameworks. Both phases are thermodynamically metastable at their respective predicted pressures, and P1–B(N 5 ) 3 remains thermodynamically metastable under ambient pressure after decompression. Electronic–structure and bonding analyses indicate that the stability of these phases originates from the combined effects of aromatic stabilization of the cyclo–N 5 − units, moderate charge transfer from boron, and strong covalent B–N interactions. After including zero–point energy and thermal corrections, the calculated energy densities at 0 GPa and 300 K are 6.24 kJ/g for P2 1 –B(N 5 ) 3 and 7.59 kJ/g for P1–B(N 5 ) 3 . These values exceed those of several representative energetic materials, including TNT and HMX, and are also competitive with previously reported nitrogen–rich high–energy–density compounds. These results demonstrate a boron-based stabilization strategy for crystalline pentazolate frameworks and provide insights into the relationship between B–N bonding and the stabilization of nitrogen-rich structures.