Materials Data on NaV2P2O9 by Materials Project
NaV2P2O9 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.35–2.74 Å. There are two inequivalent V+3.50+ sites. In the first V+3.50+ site, V+3.50+ is bonded to six O2- atoms to form VO6 octahedra that share corners with two equivalent VO6 octahedra, corners with three equivalent PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of V–O bond distances ranging from 1.83–2.10 Å. In the second V+3.50+ site, V+3.50+ 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 VO6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of V–O bond distances ranging from 2.00–2.10 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 five VO6 octahedra. The corner-sharing octahedra tilt angles range from 1–53°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent VO6 octahedra and an edgeedge with one VO6 octahedra. The corner-sharing octahedral tilt angles are 47°. There is three shorter (1.55 Å) and one longer (1.56 Å) P–O bond length. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three V+3.50+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one V+3.50+, and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one V+3.50+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one V+3.50+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, one V+3.50+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one V+3.50+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent V+3.50+ and one P5+ atom.