A Novel Polymerization of Nitrogen in Beryllium Tetranitride at High Pressure

Abstract

The stable polymeric nitrogen and polynitrogen compounds have potential applications in high-energy-density materials. For beryllium nitrides, there is one known crystalline form, Be 3 N 2 , at ambient conditions. In the present study, the structural evolutionary behaviors of beryllium polynitrdes have been studied up to 100 GPa using first-principles calculations and unbiased structure searching method combined with density functional calculations. One stable structural stoichiometry of beyrllium polynitride has been theoretically predicted at high pressures. It may be experimentally synthesizable at high pressures less than 40 GPa. It is therefore possible to synthesize BeN 4 by compressing solid Be 3 N 2 and N 2 gas under high pressure and BeN 4 may be quenching recoverable to ambient conditions. The predicted high-pressure P2 1 /c-BeN 4 compound contains a novel variety of polynitrogen, extended polymeric 3D puckered N 10 rings network. To the best of our knowledge, this is the first time that stable N 10 rings network are predicted in alkaline-earth metal polynitrides. The decomposition of P2 1 /c-BeN 4 is expected to be highly exothermic, releasing an energy of approximately 6.35 kJ•g −1 . The present results open a new avenue to synthesize polynitrogen compound and provide a key perspective toward the understanding of novel chemical bonding in nitrogen-rich compounds. Results of the present study suggest that it is possible to obtain energetic polynitrogens in main-group nitrides under high pressure.

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

“…Besides the reported dumbbell-like quasi-diatomic N 2 , armchair N-chain and S-like N-chain polymeric structures, the N 4 ring in the P 4/ mmm -MnN 4 phase as a newcomer is firstly reported. In addition, as the layered N-structures, the construction unit is generally the ring structure, such as the N 6 + N 10 ring in C 2/ m -BaN 6 , 25 the N 10 ring in P 21/ c -BeN 4 , 44 the N 12 ring in P 21/ m -GaN 5 45 and the N 18 ring in P 6/ mcc -K 2 N 16 . 29 In this work, the N 22 ring construction unit is firstly reported in the layered P 1̄-MnN 5 structure.…”

“…The armchair N-chain is found in MN 4 (M = Be, Mg, Ca, Sr, Ba, Fe, Zn, Re, Ge), 23–25,31,38–42 MN 6 (M = Fe, Ca), 24,39 MN 8 (M = Fe) 39 and MN 10 (M = Hf) 43 compounds. The layered N-structure is found in BeN 4 , 44 GaN 5 , 45 BaN 6 25 and K 2 N 16 29 compounds. Among these reported polynitrides, the BeN 4 phase with a puckered N 10 ring network is a typical high energy density material (6.35 kJ g −1 ).…”

“…Among these reported polynitrides, the BeN 4 phase with a puckered N 10 ring network is a typical high energy density material (6.35 kJ g −1 ). 44 The MN 10 -type (M = Mg, Be) 34 complexes with high energy density (3.48 kJ g −1 for MgN 10 and 5.39 kJ g −1 for BeN 10 ) are possibly synthesized at relatively low pressures (12 GPa for MgN 10 and 28 GPa for BeN 10 ). tr -FeN 4 is found to be stable at ambient pressure once being synthesized at low polymerization pressure (20 GPa).…”

Pressure‐Induced Stable Binary Compounds of Magnesium and Germanium

“…To search all potential stable ground‐state structures of the Mg–Ge system, an ab initio variable‐composition evolutionary method USPEX was performed at 50, 100, 150, and 200 GPa . Its success was demonstrated by determining the stable structures of the various compounds . All structural optimizations, calculations of the enthalpies, electronic calculations, and other structural property calculations were performed with the Vienna ab initio simulation package (VASP) .…”

“…[17][18][19] Its success was demonstrated by determining the stable structures of the various compounds. [20][21][22][23][24] All structural optimizations, calculations of the enthalpies, electronic calculations, and other structural property calculations were performed with the Vienna ab initio simulation package (VASP). [25] The Perdew-Burke-Ernzerhof generalized gradient approximation (GGA) [26] was chosen as the exchange-correlation functional, and projector-augmented wave (PAW) [27] potentials were adopted to describe the ionic potentials.…”