Stabilized Nitrogen Framework Anions in the Ga–N System

Abstract

Nitrogen-rich compounds have attracted significant fundamental and practical interest owing to their ability to accommodate diverse nitrogen-bonding patterns and their feasibility as high-energy-density materials. Herein, we examine a wide range of chemical compositions in the compressed Ga–N system using first-principles structural search and experimental preparation using a laser-heated diamond anvil cell. Our investigations have theoretically identified three thermodynamically stable stoichiometriesGaN15, GaN10, and GaN5with surprisingly versatile polymeric nitrogen framework topologies. Strikingly, our results show that the required synthetic pressures for forming polymeric nitrogen phases in GaN10 and GaN5 are much lower than that for pure solid nitrogen. Finally, we evaluated the energy involved in decomposing the compounds and validated that they are promising candidates for high-energy-density materials. These findings have broad implications for designing and synthesizing novel nitrogen-rich compounds through the reaction between p electron elements and nitrogen at modest pressures and for nitrogen chemistry under extreme conditions.

A 2D Ba2N Electride for Transition Metal-Free N2 Dissociation under Mild Conditions

“…The sample collected after pure 14 N 2 treatment showed a main signal centered at 1447 cm – 1 . After the 15 N 2 treatment, the signal was split into two peaks at 1397 and 1418 cm –1 , which agreed well with the isotopic effect induced by the change of 14 N 2 to 15 N 2 and 15 N 14 N. These signals can be attributed to stretching vibrations of (N 2 ) 2 – anions, so-called diazenide, as identified in high-pressure stabilized inorganic materials and organic complexes. ,− Moreover, the Raman signal for (N 2 ) 2 – anions almost disappeared when Ba 2 N was further heated in He at 600 °C (Figure S18). Therefore, N 2 desorption in the low-temperature range (290–570 °C) is confirmed to result from the release of (N 2 ) 2 – anions that are formed as intermediates of N 2 dissociation on/in Ba 2 N.…”

Two Ultrahigh-Energy-Density Layered Cerium Polynitrides with Molecular Sieve Channel

“…34−36 Among them, the P4/nmm-BeN 4 , γ-BeN 4 , δ-BeN 4 , WN 6 , MN 10 , and MN 15 compounds are recoverable at ambient pressure. Experimentally, LiN 5 and CsN 5 with N 5 rings, 37,38 K 2 N 6 with N 6 ring, 39 MgN 4 , Mg 2 N 4 , and tr-BeN 4 with armchair chains, 40−42 and layered GaN 5 43 have been synthesized at 45−85 GPa. Furthermore, LiN 5 , tr-BeN 4 , and Mg 2 N 4 can be quenched to ambient conditions.…”

“…For instances, P 4/ nmm -BeN 4 with N 4 ring, MN 10 (M = Be, Mg, and Zn), and MN 15 (M = Al, Ga, Sc, and Y) compounds with N 5 rings, − R 3̅ m -WN 6 with N 6 ring, γ-BeN 4 and δ-BeN 4 with armchair chains, and layered BeN 4 , GaN 5 , and ScN 5 . − Among them, the P 4/ nmm -BeN 4 , γ -BeN 4 , δ -BeN 4 , WN 6 , MN 10 , and MN 15 compounds are recoverable at ambient pressure. Experimentally, LiN 5 and CsN 5 with N 5 rings, , K 2 N 6 with N 6 ring, MgN 4 , Mg 2 N 4 , and tr -BeN 4 with armchair chains, − and layered GaN 5 have been synthesized at 45–85 GPa. Furthermore, LiN 5 , tr -BeN 4 , and Mg 2 N 4 can be quenched to ambient conditions.…”

One-Dimensional Non-coplanar Nitrogen Chains in Manganese Tetranitride under High Pressure

“…In the angle-resolved XRD pattern at 108 GPa, there was a significant overlap of Bragg peaks between the reacted/unreacted sample and gasket due to the tail of the X-ray beam spot (Figure S3). This phenomenon is expected in the synthesized new phases by high-pressure and high-temperature treatment. , So, we think the quality of Rietveld refinement between calculation and experiment is tolerable, considering the lower content of MnN 4 compared to the unreacted Mn sample. By comparing the XRD patterns with the crystal structures proposed in the previous study, − we found that the new peaks at 108 GPa corresponded to a new nitride MnN 4 with P -1 symmetry.…”

“…This phenomenon is expected in the synthesized new phases by high-pressure and high-temperature treatment. 36,42 So, we think the quality of Rietveld refinement between calculation and experiment is tolerable, considering the lower content of MnN 4 compared to the unreacted Mn sample. By comparing the XRD patterns with the crystal structures proposed in the previous study, 39−41 S1).…”