Materials Data on Na4P2O7 by Materials Project
Na4P2O7 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.33–2.83 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.37–2.71 Å. In the third Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.36–2.60 Å. In the fourth Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.30–2.45 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 NaO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 25–57°. There are a spread of P–O bond distances ranging from 1.53–1.65 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent NaO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–67°. There is three shorter (1.53 Å) and one longer (1.67 Å) P–O bond length. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one P5+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+ and two P5+ atoms. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Na1+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one P5+ atom.