Synthesis and crystal structure of silicon pernitride SiN2 at 140 GPa

Pascal L Jurzick; Georg Krach; Lukas Brüning; Wolfgang Schnick; Maxim Bykov

doi:10.1107/S2056989023008058

Synthesis and crystal structure of silicon pernitride SiN₂ at 140 GPa

Acta Crystallogr E Crystallogr Commun. 2023 Sep 19;79(Pt 10):923-925. doi: 10.1107/S2056989023008058. eCollection 2023 Oct 1.

Authors

Pascal L Jurzick¹, Georg Krach², Lukas Brüning¹, Wolfgang Schnick², Maxim Bykov¹

Affiliations

¹ Institute of Inorganic Chemistry, University of Cologne, Greinstrasse 6, 50939 Cologne, Germany.
² Department of Chemistry, University of Munich (LMU), Butenandtstrasse 5-13 (D), 81377 Munich, Germany.

Abstract

Silicon pernitride, SiN₂, was synthesized from the elements at 140 GPa in a laser-heated diamond anvil cell. Its crystal structure was solved and refined by means of synchrotron-based single-crystal X-ray diffraction data. The title compound crystallizes in the pyrite structure type (space group Pa , No. 205). The Si atom occupies a site with multiplicity 4 (Wyckoff letter b, site symmetry ..), while the N atom is located on a site with multiplicity 8 (Wyckoff letter c, site symmetry .3.). The crystal structure of SiN₂ is comprised of slightly distorted [SiN₆] octa-hedra inter-connected with each other by sharing vertices. Crystal chemical analysis of bond lengths suggests that Si has a formal oxidation state of +IV, while nitro-gen forms pernitride anions (N-N)^4-.

Keywords: crystal structure; high pressure; nitrides; pernitrides; silicon nitrides.

Grants and funding

Funding for this research was provided by: Deutsche Forschungsgemeinschaft (grant No. BY112/2-1 to Maxim Bykov). A PhD scholarship for GK from the Friedrich Naumann Foundation for Freedom with funds from the Federal Ministry of Education and Research (BMBF) is gratefully acknowledged.