Materials Data on Si2Sn2O7 by Materials Project
Sn2Si2O7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Sn3+ sites. In the first Sn3+ site, Sn3+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of Sn–O bond distances ranging from 2.01–2.18 Å. In the second Sn3+ site, Sn3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Sn–O bond distances ranging from 2.32–2.83 Å. In the third Sn3+ site, Sn3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Sn–O bond distances ranging from 2.31–2.49 Å. In the fourth Sn3+ site, Sn3+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with seven SiO4 tetrahedra. There are a spread of Sn–O bond distances ranging from 2.02–2.31 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three SnO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 29–54°. There are a spread of Si–O bond distances ranging from 1.63–1.67 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four SnO6 octahedra. The corner-sharing octahedra tilt angles range from 39–49°. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent SnO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–59°. There are a spread of Si–O bond distances ranging from 1.62–1.72 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three SnO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–63°. There are a spread of Si–O bond distances ranging from 1.62–1.77 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Sn3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Sn3+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Sn3+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Sn3+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Sn3+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Sn3+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two Sn3+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Si4+ atoms. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to one Sn3+ and one Si4+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Sn3+ and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a 1-coordinate geometry to two Sn3+ and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a distorted single-bond geometry to two Sn3+ and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Sn3+ and two Si4+ atoms. In the fourteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Sn3+ and one Si4+ atom.