Materials Data on NaNi2P2O9 by Materials Project

Abstract

NaNi2P2O9 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 2.29–2.52 Å. There are two inequivalent Ni+3.50+ sites. In the first Ni+3.50+ site, Ni+3.50+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two equivalent NiO6 octahedra, corners with three equivalent PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. There are a spread of Ni–O bond distances ranging from 1.92–2.03 Å. In the second Ni+3.50+ site, Ni+3.50+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two equivalent NiO6 octahedra, corners with four PO4 tetrahedra, and edges with two equivalent NiO6 octahedra. The corner-sharing octahedral tilt angles are 52°. There are a spread of Ni–O bond distances ranging from 1.98–2.08 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 NiO6 octahedra. The corner-sharing octahedra tilt angles range from 25–53°. There is one shorter (1.52 Å) and three longer (1.55 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 NiO6 octahedra and an edgeedge with one NiO6 octahedra. The corner-sharing octahedral tilt angles are 49°. There is two shorter (1.53 Å) and two longer (1.57 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 Ni+3.50+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ni+3.50+, and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ni+3.50+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ni+3.50+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ni+3.50+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Ni+3.50+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ni+3.50+ and one P5+ atom.