Materials Data on Li2NiP2O7 by Materials Project

Li2NiP2O7 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Li–O bond distances ranging from 1.93–2.11 Å. In the second Li1+ site, Li1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Li–O bond distances ranging from 1.92–2.66 Å. Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Ni–O bond distances ranging from 2.02–2.17 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 48–50°. There are a spread of P–O bond distances ranging from 1.52–1.63 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 26–53°. There is three shorter (1.53 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 one Li1+, one Ni2+, and one P5+ atom. In the second O2- site, O2- is bonded in a 5-coordinate geometry to three Li1+, one Ni2+, and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Ni2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Ni2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Li1+, one Ni2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Ni2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms.