Materials Data on NiP2O7 by Materials Project
NiP2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ni4+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with six PO4 tetrahedra and an edgeedge with one NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 2.01–2.15 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 NiO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–55°. There are a spread of P–O bond distances ranging from 1.51–1.60 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent NiO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 9–40°. There is three shorter (1.52 Å) and one longer (1.62 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 two equivalent Ni4+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ni4+ and one P5+ atom. In the third O2- site, O2- is bonded in a linear geometry to one Ni4+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ni4+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the sixth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Ni4+ and one P5+ atom.