Materials Data on Na4VP2O9 by Materials Project
Na4VO(PO4)2 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with five PO4 tetrahedra and edges with two equivalent VO6 octahedra. There are a spread of Na–O bond distances ranging from 2.34–2.52 Å. In the second 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 2.33–2.48 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.29–2.86 Å. In the fourth Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.36–2.91 Å. V4+ is bonded to six O2- atoms to form VO6 octahedra that share corners with two equivalent VO6 octahedra, corners with four PO4 tetrahedra, and edges with two equivalent NaO6 octahedra. The corner-sharing octahedral tilt angles are 44°. There are a spread of V–O bond distances ranging from 1.72–2.10 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 two equivalent VO6 octahedra and corners with three equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 43–74°. There is two shorter (1.54 Å) and two longer (1.58 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 two equivalent NaO6 octahedra and corners with two equivalent VO6 octahedra. The corner-sharing octahedra tilt angles range from 16–47°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded to three Na1+ and one P5+ atom to form distorted corner-sharing ONa3P trigonal pyramids. 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 five Na1+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one V4+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one V4+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one V4+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one V4+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and two equivalent V4+ atoms.