title: Calculations predict a stable molecular crystal of N8.
abstract: Nitrogen, one of the most abundant elements in nature, forms the highly stable N2 molecule in its elemental state. In contrast, polynitrogen compounds comprising only nitrogen atoms are rare, and no molecular crystal made of these compounds has been prepared. Here, we predict the existence of such a molecular solid, consisting of N8 molecules, that is metastable even at ambient pressure. In the solid state, the N8 monomers retain the same structure and bonding pattern as those they adopt in the gas phase. The interactions that bind N8 molecules together are weak van der Waals and electrostatic forces. The solid is, according to calculations, more stable than a previously reported polymeric nitrogen solid, including at low pressure (below 20 GPa). The structure and properties of the N8 molecular crystal are discussed and a possible preparation strategy is suggested.
authors.affiliation: Institute of Chemistry and The Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem 91904, Israel.
authors.forename: Barak
authors.initials: B
authors.lastname: Hirshberg
authors.affiliation: 1] Institute of Chemistry and The Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem 91904, Israel [2] Department of Chemistry, University of California, Irvine, California 92697, USA.
authors.forename: R Benny
authors.initials: RB
authors.lastname: Gerber
authors.affiliation: Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA.
authors.forename: Anna I
authors.initials: AI
authors.lastname: Krylov
mesh_terms: D003460:Crystallization; D009584:Nitrogen / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D009584:Nitrogen