Materials Data on SiP2O7 by Materials Project
SiP2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Si4+ is bonded to six O2- atoms to form SiO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.76–1.80 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent SiO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 33–37°. There is three shorter (1.52 Å) and one longer (1.61 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent SiO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 16–43°. There are a spread of P–O bond distances ranging from 1.51–1.60 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear 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 bent 150 degrees geometry to one Si4+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 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. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Si4+ and one P5+ atom.