Synthesis and crystal structure of silicon pernitride SiN(2) at 140 GPa

Silicon pernitride, SiN(2), 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 [Image: see text] , No. 205). The Si atom occupies a site with multiplicity 4 (Wyckoff letter b, site symmetry . [Image: see text] .), while the N atom is located on a site with multiplicity 8 (Wyckoff letter c, site symmetry .3.). The crystal structure of SiN(2) is comprised of slightly distorted [SiN(6)] octa­hedra inter­connected with each other by sharing vertices. Crystal chemical analysis of bond lengths suggests that Si has a formal oxidation state of +IV, while nitro­gen forms pernitride anions (N—N)(4–).