Materials Data on Pr4Si2S3O7 by Materials Project
Pr4Si2S3O7 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. there are two inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 9-coordinate geometry to three S2- and six O2- atoms. There are one shorter (2.93 Å) and two longer (2.97 Å) Pr–S bond lengths. There are a spread of Pr–O bond distances ranging from 2.52–2.64 Å. In the second Pr3+ site, Pr3+ is bonded in a 6-coordinate geometry to three S2- and three O2- atoms. There are two shorter (2.89 Å) and one longer (2.91 Å) Pr–S bond lengths. There are one shorter (2.42 Å) and two longer (2.54 Å) Pr–O bond lengths. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SPr4O2 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 65°. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted square co-planar geometry to four equivalent Pr3+ atoms. In the second S2- site, S2- is bonded to four equivalent Pr3+ and two equivalent O2- atoms to form distorted SPr4O2 octahedra that share corners with four equivalent SiO4 tetrahedra. Both S–O bond lengths are 3.29 Å. In the third S2- site, S2- is bonded in a 4-coordinate geometry to four Pr3+ atoms. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Si4+ and one S2- atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Pr3+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+ and one Si4+ atom.