DOE OSTI2020
LiNiPO4 is Ilmenite-derived structured and 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 to six O2- atoms to form LiO6 octahedra that share corners with four NiO6 octahedra, corners with two PO4 tetrahedra, edges with two equivalent LiO6 octahedra, edges with two NiO6 octahedra, and edges with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–67°. There are a spread of Li–O bond distances ranging from 2.08–2.21 Å. In the second Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with four NiO6 octahedra, corners with two PO4 tetrahedra, edges with two equivalent LiO6 octahedra, edges with two NiO6 octahedra, and edges with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–65°. There are a spread of Li–O bond distances ranging from 2.10–2.16 Å. There are two inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with four LiO6 octahedra, corners with four equivalent NiO6 octahedra, corners with four PO4 tetrahedra, edges with two LiO6 octahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–66°. There are a spread of Ni–O bond distances ranging from 2.06–2.17 Å. In the second Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with four LiO6 octahedra, corners with four equivalent NiO6 octahedra, corners with four PO4 tetrahedra, edges with two LiO6 octahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–67°. There are a spread of Ni–O bond distances ranging from 2.06–2.18 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 LiO6 octahedra, corners with four NiO6 octahedra, an edgeedge with one NiO6 octahedra, and edges with two LiO6 octahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two LiO6 octahedra, corners with four NiO6 octahedra, an edgeedge with one NiO6 octahedra, and edges with two LiO6 octahedra. The corner-sharing octahedra tilt angles range from 50–57°. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Li1+, one Ni2+, and one P5+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Li1+, one Ni2+, and one P5+ atom. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Li1+, two Ni2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Li1+, two Ni2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Li1+, two Ni2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Li1+, one Ni2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Li1+, one Ni2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Li1+, two Ni2+, and one P5+ atom.