Materials Data on Si5P6O25 by Materials Project
Si5O(PO4)6 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are three inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to six equivalent O2- atoms to form SiO6 octahedra that share corners with six equivalent PO4 tetrahedra. All Si–O bond lengths are 1.78 Å. In the second Si4+ site, Si4+ is bonded to six O2- atoms to form SiO6 octahedra that share corners with six equivalent PO4 tetrahedra. There is three shorter (1.76 Å) and three longer (1.80 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra and corners with three equivalent PO4 tetrahedra. There is one shorter (1.61 Å) and three longer (1.63 Å) Si–O bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three SiO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 28–46°. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Si4+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Si4+ and one P5+ atom. In the third O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Si4+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Si4+ and one P5+ atom.