Materials Data on Sr2Si5N8 by Materials Project
Sr2Si5N8 is Chalcostibite-like structured and crystallizes in the orthorhombic Pmn2_1 space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to ten N3- atoms. There are a spread of Sr–N bond distances ranging from 2.55–3.29 Å. In the second Sr2+ site, Sr2+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of Sr–N bond distances ranging from 2.57–2.92 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four N3- atoms to form corner-sharing SiN4 tetrahedra. There are a spread of Si–N bond distances ranging from 1.68–1.79 Å. In the second Si4+ site, Si4+ is bonded to four N3- atoms to form corner-sharing SiN4 tetrahedra. There is one shorter (1.68 Å) and three longer (1.78 Å) Si–N bond length. In the third Si4+ site, Si4+ is bonded to four N3- atoms to form corner-sharing SiN4 tetrahedra. There is one shorter (1.72 Å) and three longer (1.73 Å) Si–N bond length. In the fourth Si4+ site, Si4+ is bonded to four N3- atoms to form corner-sharing SiN4 tetrahedra. There are a spread of Si–N bond distances ranging from 1.69–1.79 Å. There are six inequivalent N3- sites. In the first N3- site, N3- is bonded in a trigonal non-coplanar geometry to one Sr2+ and three Si4+ atoms. In the second N3- site, N3- is bonded in a 5-coordinate geometry to three Sr2+ and two Si4+ atoms. In the third N3- site, N3- is bonded in a distorted trigonal planar geometry to one Sr2+ and three Si4+ atoms. In the fourth N3- site, N3- is bonded in a distorted trigonal planar geometry to one Sr2+ and three Si4+ atoms. In the fifth N3- site, N3- is bonded in a 2-coordinate geometry to three Sr2+ and two Si4+ atoms. In the sixth N3- site, N3- is bonded in a 2-coordinate geometry to three Sr2+ and two Si4+ atoms.