DOE OSTI2020
Ti3Cr2Mn(PO4)6 crystallizes in the trigonal R3 space group. The structure is three-dimensional. there are three inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six PO4 tetrahedra and a faceface with one CrO6 octahedra. There are three shorter (1.90 Å) and three longer (2.10 Å) Ti–O bond lengths. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six PO4 tetrahedra. There is three shorter (1.88 Å) and three longer (2.01 Å) Ti–O bond length. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six PO4 tetrahedra. There is three shorter (1.89 Å) and three longer (2.09 Å) Ti–O bond length. There are two inequivalent Cr2+ sites. In the first Cr2+ site, Cr2+ is bonded to six O2- atoms to form distorted CrO6 octahedra that share corners with six PO4 tetrahedra, a faceface with one TiO6 octahedra, and a faceface with one MnO6 octahedra. There are three shorter (2.19 Å) and three longer (2.21 Å) Cr–O bond lengths. In the second Cr2+ site, Cr2+ is bonded in a distorted hexagonal planar geometry to six O2- atoms. There are three shorter (2.28 Å) and three longer (2.31 Å) Cr–O bond lengths. Mn2+ is bonded to six O2- atoms to form distorted MnO6 octahedra that share corners with six PO4 tetrahedra and a faceface with one CrO6 octahedra. There are three shorter (2.05 Å) and three longer (2.22 Å) Mn–O bond lengths. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CrO6 octahedra, a cornercorner with one MnO6 octahedra, and corners with three TiO6 octahedra. The corner-sharing octahedra tilt angles range from 23–51°. There are a spread of P–O bond distances ranging from 1.49–1.58 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CrO6 octahedra, a cornercorner with one MnO6 octahedra, and corners with three TiO6 octahedra. The corner-sharing octahedra tilt angles range from 22–52°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Ti4+ and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ti4+, one Cr2+, and one P5+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Mn2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Ti4+, one Cr2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ti4+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Cr2+, one Mn2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ti4+, one Cr2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ti4+ and one P5+ atom.