Stabilization of hexazine rings in potassium polynitride at high pressure

TL;DR

This paper reports the synthesis and stabilization of N6 hexazine rings in potassium polynitride under high pressure, revealing a new highly energetic polynitrogen compound with potential applications.

Contribution

The study demonstrates the formation of stable N6 hexazine rings in K2N6 from laser-heated K azide at high pressures, supported by experimental and theoretical analysis.

Findings

N6 hexazine rings are stabilized in K2N6 at pressures above 20 GPa.

The compound exhibits metallic luster and matches predicted properties.

Potential for future recovery and energetic applications.

Abstract

Polynitrogen molecules represent the ultimate high energy-density materials as they have a huge potential chemical energy originating from their high enthalpy. However, synthesis and storage of such compounds remain a big challenge because of difficulties to find energy efficient synthetic routes and stabilization mechanisms. Compounds of metals with nitrogen represent promising candidates for realization of energetic polynitrogen compounds, which are also environmentally benign. Here we report the synthesis of polynitrogen planar N6 hexazine rings, stabilized in K2N6 compound, which was formed from K azide upon laser heating in a diamond anvil cell at high pressures in excess of 45 GPa and remains metastable down to 20 GPa. Synchrotron X-ray diffraction and Raman spectroscopy are used to identify this material, also exhibiting metallic luster, being all consistent with theoretically predicted structural, vibrational and electronic properties. The documented here N6 hexazine rings represent new highly energetic polynitrogens, which have a potential for future recovery and utilization.