Pressure-stabilized polymerization of nitrogen in manganese nitrides at ambient and high pressures

Abstract

A systematic high pressure study is performed on Mn–N compounds by using the particle swarm optimization methodology.

New Transformation Pathway of cg-N from HeN4 under Moderate Pressure

“…Interestingly, the energy densities of the P 2 1 2 1 2 1 -HeN 4 phase and the o -N phase are found to be 12.81 and 10.80 kJ/g, respectively, which are much higher than that of commercially available explosive materials such as TNT (4.30 kJ/g). Furthermore, it is evident from the results in Table that the P 2 1 2 1 2 1 -HeN 4 phase and the o -N phase exhibit an outstanding detonation performance as gauged by the detonation pressure and detonation velocity, which are both significantly higher than that of TNT (6.90 GPa, 19.00 km/s) …”

“…The detonation velocity and detonation pressure are calculated using the Kamlet–Jacobs semi-empirical equation given by V d = 1.01­( NM 0.5 E d 0.5 ) 0.5 (1 + 1.30ρ) and P d = 15.58ρ 2 NM 0.5 E d 0.5 . The crystal orbital Hamilton population (COHP) is calculated using the LOBSTER program …”

“…Furthermore, it is evident from the results in Table 1 that the P2 1 2 1 2 1 -HeN 4 phase and the o-N phase exhibit an outstanding detonation performance as gauged by the detonation pressure and detonation velocity, which are both significantly higher than that of TNT (6.90 GPa, 19.00 km/s). 42…”

Prediction of metastable phase of the Sc–N system in the N-rich region under high pressure

“…From the presented results in Table 2, the energy densities of the P 1̄-ScN 8 , P 1-ScN 9 and P 1-ScN 11 phases are 6.72, 5.74 and 6.44 kJ g −1 , respectively, which are far larger than that of reported high-energy materials, such as CNO (2.2 kJ g −1 ), LiN 5 (2.72 kJ g −1 ) and TNT (4.3 kJ g −1 ). 32,33 More importantly, the detonation pressure and detonation velocity of P 1̄-ScN 8 , P 1-ScN 9 and P 1-ScN 11 are respectively (238.11 GPa, 19.60 km s −1 ), (198.69 GPa, 18.09 km s −1 ) and (217.88 GPa, 18.98 km s −1 ), which are significantly larger than those of TNT (19.00 GPa, 6.9 km s −1 ). Therefore, the prominent energy properties indicate their potential broad application in the field of propellants and explosives.…”

The New High-Pressure Phases of Nitrogen-Rich Ag–N Compounds

“…A series of polynitrogen structures has been reported in theoretical studies. Typically, the novel N 4 ring is reported for P4/mmm-MnN 4 , Cm-Al 2 N 7 , P-1-Na 2 N 8 , P2 1 /c-Li 2 N 4 , C2/m-MgN 4 and Immm-AlN 4 compounds [19][20][21][22]. Especially, the regular N 4 rings results in a superhard property of P4/mmm-MnN 4 and Cm-Al 2 N 7 .…”