Materials Data on Li2CrPO4F by Materials Project
Li2CrPO4F crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a 6-coordinate geometry to four O2- and two F1- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.34 Å. There are one shorter (1.89 Å) and one longer (2.34 Å) Li–F bond lengths. In the second Li1+ site, Li1+ is bonded in a 5-coordinate geometry to four O2- and one F1- atom. There are a spread of Li–O bond distances ranging from 2.07–2.21 Å. The Li–F bond length is 1.92 Å. In the third Li1+ site, Li1+ is bonded to four O2- and two F1- atoms to form distorted LiO4F2 octahedra that share a cornercorner with one LiO4F2 octahedra, corners with two CrO4F2 octahedra, corners with four PO4 tetrahedra, edges with two CrO4F2 octahedra, and a faceface with one LiO4F2 octahedra. The corner-sharing octahedra tilt angles range from 23–75°. There are a spread of Li–O bond distances ranging from 2.04–2.31 Å. There are one shorter (2.17 Å) and one longer (2.49 Å) Li–F bond lengths. There are two inequivalent Cr2+ sites. In the first Cr2+ site, Cr2+ is bonded to four O2- and two equivalent F1- atoms to form CrO4F2 octahedra that share corners with two equivalent LiO4F2 octahedra, corners with four PO4 tetrahedra, edges with two equivalent LiO4F2 octahedra, and edges with two equivalent CrO4F2 octahedra. The corner-sharing octahedral tilt angles are 40°. There are two shorter (2.07 Å) and two longer (2.16 Å) Cr–O bond lengths. Both Cr–F bond lengths are 2.32 Å. In the second Cr2+ site, Cr2+ is bonded to four O2- and two equivalent F1- atoms to form CrO4F2 octahedra that share corners with two equivalent LiO4F2 octahedra, corners with four PO4 tetrahedra, edges with two equivalent LiO4F2 octahedra, and edges with two equivalent CrO4F2 octahedra. The corner-sharing octahedral tilt angles are 23°. There are two shorter (2.08 Å) and two longer (2.11 Å) Cr–O bond lengths. Both Cr–F bond lengths are 2.36 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 four equivalent LiO4F2 octahedra and corners with four CrO4F2 octahedra. The corner-sharing octahedra tilt angles range from 52–66°. There are a spread of P–O bond distances ranging from 1.55–1.58 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four equivalent LiO4F2 octahedra and corners with four CrO4F2 octahedra. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Li1+, two equivalent Cr2+, and one P5+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Li1+, one Cr2+, and one P5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Li1+, two equivalent Cr2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted tetrahedral geometry to three Li1+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Li1+, one Cr2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Li1+ and one P5+ atom. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a 1-coordinate geometry to three Li1+ and two equivalent Cr2+ atoms. In the second F1- site, F1- is bonded in a 6-coordinate geometry to four Li1+ and two equivalent Cr2+ atoms.