Materials Data on Gd4Si2S3O7 by Materials Project
Gd4Si2S3O7 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. there are two inequivalent Gd3+ sites. In the first Gd3+ site, Gd3+ is bonded in a 6-coordinate geometry to three S2- and three O2- atoms. There are two shorter (2.82 Å) and one longer (2.83 Å) Gd–S bond lengths. There are one shorter (2.34 Å) and two longer (2.47 Å) Gd–O bond lengths. In the second Gd3+ site, Gd3+ is bonded in a 9-coordinate geometry to three S2- and six O2- atoms. There are one shorter (2.89 Å) and two longer (2.91 Å) Gd–S bond lengths. There are a spread of Gd–O bond distances ranging from 2.41–2.59 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SGd4O2 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 64°. There is three shorter (1.64 Å) and one longer (1.65 Å) Si–O bond length. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to four Gd3+ atoms. In the second S2- site, S2- is bonded to four equivalent Gd3+ and two equivalent O2- atoms to form distorted SGd4O2 octahedra that share corners with four equivalent SiO4 tetrahedra. Both S–O bond lengths are 3.17 Å. In the third S2- site, S2- is bonded in a 4-coordinate geometry to four equivalent Gd3+ and twelve O2- atoms. There are eight shorter (3.18 Å) and four longer (3.27 Å) S–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Si4+ and one S2- atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three Gd3+, one Si4+, and one S2- atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Gd3+, one Si4+, and one S2- atom.