Materials Data on Na4TiP2O9 by Materials Project

Na4TiO(PO4)2 crystallizes in the orthorhombic Cmme space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 4-coordinate geometry to eight O2- atoms. There are four shorter (2.46 Å) and four longer (2.91 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded in a 4-coordinate geometry to eight O2- atoms. There are four shorter (2.42 Å) and four longer (2.89 Å) Na–O bond lengths. 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 2.21–2.52 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra and corners with four equivalent PO4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. There is two shorter (1.91 Å) and four longer (2.00 Å) Ti–O bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent TiO6 octahedra. The corner-sharing octahedral tilt angles are 42°. There is two shorter (1.53 Å) and two longer (1.58 Å) P–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to three Na1+, one Ti4+, and one P5+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Na1+ and one P5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+ and two equivalent Ti4+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Na1+ and one P5+ atom.