CHN7 – A Molecule Like Almost Solid Nitrogen

Abstract

In this communication, we present the crystal structure of an energetic salt -a dysprosium 5,5 0 -azotetrazolate hydrate with a 5-azido-2H-tetrazole adduct and, thereby, the first complete crystal structure of a 5-azidotetrazole molecule (CHN 7 ). Furthermore, it is the first structural evidence for a 2H-tautomer of this molecule: By careful analysis of the hydrogen bonding in the crystal, we could unambiguously locate the hydrogen atom at the N2 position. The extremely sensitive and energetic 5-azidotetrazole presented herein is the nitrogen-richest organic molecule which has ever been completely structurally characterized. The dysprosium compound is the first cocrystal of a 5,5 0 -azotetrazolate anion with a neutral 5-substituted tetrazole derivative adduct. It is also the first structurally characterized azotetrazolate of an f-block element. Our result shows that 5-azido-2H-tetrazole is the product of Lewis acidic decomposition of 5,5 0 -azotetrazole in water in presence of nitrate.