Aromatic hexazine [N6]4− anion featured in the complex structure of the high-pressure potassium nitrogen compound K9N56

Abstract

Recent high-pressure synthesis of pentazolates and subsequent stabilization of the aromatic [N5 -] anion at atmospheric pressure had an immense impact on nitrogen chemistry. Here, we present the first synthesis of an aromatic hexazine [N6] 4anion realized in high-pressure potassium nitride K9N56 at 46 and 61 GPa. The extremely complex structure of K9N56 was solved based on synchrotron single-crystal X-ray diffraction and corroborated by density functional theory calculations. This result resolves a long-standing question of the aromatic hexazine stability and the possibility of its synthesis.

Bond-alternated and bond-equalized hexazine derivatives

“…These systems are in some sense related to the experimentally known N 6 4− . 45 In the latter, two of the antibonding π* levels are occupied, whereas in the former, they are partially occupied. This makes us hopeful about the possible experimental realization of these systems.…”

Structure determination of ζ-N2 from single-crystal X-ray diffraction and theoretical suggestion for the formation of amorphous nitrogen

“…The samples were compressed to pressures of 54 GPa (DAC1), 63 GPa (DAC2), 70 GPa (DAC3) and 86 GPa (DAC4), and heated to a maximum temperature of 2600(200) K, 3400(200) K, 2500(200) K and to an estimate temperature of 3000 K, respectively. The reaction products of molecular nitrogen with the laser absorbers are described elsewhere 28 , 29 . In all samples, molecular nitrogen surrounding the laser absorbers was also heated, albeit likely to a lower temperature, producing multiple tiny ( < 500 nm) high-quality single-crystals on which Raman spectroscopy, powder X-ray diffraction and single-crystal X-ray diffraction (SCXRD) data were collected.…”

Geometries and stabilities of chromium doped nitrogen clusters: mass spectrometry and density functional theory studies

“…Wang et al 25 reported the synthesis of planar N 6 2À hexazine dianions through potassium azide (KN 3 ) under high pressure. Laniel et al 26 conducted a study on the synthesis of the K 9 N 56 compound by laser heating under high pressure and a first principles calculations. The results revealed that the K 9 N 56 compound comprises a complex arrangement of planar aromatic hexazine [N 6 ] 4À and [N 5 ] À rings, along with neutral nitrogen dimers.…”