DOE OSTI2020
MnFe2(PO4)3 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are three inequivalent Mn3+ sites. In the first Mn3+ site, Mn3+ is bonded to six O2- atoms to form distorted MnO6 octahedra that share corners with four equivalent FeO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–52°. There are a spread of Mn–O bond distances ranging from 1.90–2.34 Å. In the second Mn3+ site, Mn3+ is bonded to six O2- atoms to form distorted MnO6 octahedra that share corners with four FeO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–51°. There are a spread of Mn–O bond distances ranging from 1.90–2.33 Å. In the third Mn3+ site, Mn3+ is bonded to six O2- atoms to form distorted MnO6 octahedra that share corners with four equivalent FeO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–52°. There are a spread of Mn–O bond distances ranging from 1.91–2.34 Å. There are five inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four FeO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–50°. There are a spread of Fe–O bond distances ranging from 1.94–2.18 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent MnO6 octahedra, corners with two equivalent FeO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–52°. There are a spread of Fe–O bond distances ranging from 1.93–2.19 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four equivalent FeO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–50°. There are a spread of Fe–O bond distances ranging from 1.93–2.17 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four MnO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–52°. There are a spread of Fe–O bond distances ranging from 1.95–2.17 Å. In the fifth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four equivalent MnO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–51°. There are a spread of Fe–O bond distances ranging from 1.95–2.17 Å. There are eight inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two MnO6 octahedra, corners with two equivalent FeO6 octahedra, and an edgeedge with one MnO6 octahedra. The corner-sharing octahedra tilt angles range from 44–54°. There is two shorter (1.55 Å) and two longer (1.56 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one MnO6 octahedra, corners with three FeO6 octahedra, and an edgeedge with one MnO6 octahedra. The corner-sharing octahedra tilt angles range from 40–54°. There are a spread of P–O bond distances ranging from 1.54–1.57 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two MnO6 octahedra, corners with two equivalent FeO6 octahedra, and an edgeedge with one MnO6 octahedra. The corner-sharing octahedra tilt angles range from 44–54°. There is two shorter (1.55 Å) and two longer (1.56 Å) P–O bond length. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one MnO6 octahedra, corners with three FeO6 octahedra, and an edgeedge with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 44–56°. There are a spread of P–O bond distances ranging from 1.52–1.58 Å. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one MnO6 octahedra, corners with three FeO6 octahedra, and an edgeedge with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 43–56°. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four FeO6 octahedra and an edgeedge with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 42–56°. There is two shorter (1.53 Å) and two longer (1.58 Å) P–O bond length. In the seventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two MnO6 octahedra, corners with two FeO6 octahedra, and an edgeedge with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 43–55°. There are a spread of P–O bond distances ranging from 1.52–1.58 Å. In the eighth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent MnO6 octahedra, corners with two FeO6 octahedra, and an edgeedge with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 42–55°. There are a spread of P–O bond distances ranging from 1.52–1.58 Å. There are twenty-eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Mn3+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Mn3+ and one P5+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one Mn3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Mn3+, one Fe3+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mn3+, one Fe3+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Mn3+, one Fe3+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to one Mn3+, one Fe3+, and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Fe3+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Fe3+ and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mn3+, one Fe3+, and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Fe3+ and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a 3-coordinate geometry to two Fe3+ and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mn3+, one Fe3+, and one P5+ atom. In the nineteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mn3+, one Fe3+, and one P5+ atom. In the twentieth O2- site, O2- is bonded in a 3-coordinate geometry to one Mn3+, one Fe3+, and one P5+ atom. In the twenty-first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn3+ and one P5+ atom. In the twenty-second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Mn3+ and one P5+ atom. In the twenty-third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn3+ and one P5+ atom. In the twenty-fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the twenty-fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the twenty-sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the twenty-seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the twenty-eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom.