DOE OSTI2020
Fe2Cd5(P2O7)4 crystallizes in the orthorhombic C222_1 space group. The structure is three-dimensional. Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.91–2.21 Å. There are four inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cd–O bond distances ranging from 2.29–2.46 Å. In the second Cd2+ site, Cd2+ is bonded to six O2- atoms to form distorted CdO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Cd–O bond distances ranging from 2.20–2.47 Å. In the third Cd2+ site, Cd2+ is bonded to six O2- atoms to form distorted CdO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Cd–O bond distances ranging from 2.17–2.41 Å. In the fourth Cd2+ site, Cd2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cd–O bond distances ranging from 2.25–2.80 Å. There are four 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 FeO6 octahedra, corners with two equivalent CdO6 octahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–54°. There are a spread of P–O bond distances ranging from 1.50–1.64 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CdO6 octahedra, corners with two equivalent FeO6 octahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 25–55°. There are a spread of P–O bond distances ranging from 1.52–1.64 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO6 octahedra, corners with two equivalent CdO6 octahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–53°. There are a spread of P–O bond distances ranging from 1.51–1.61 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CdO6 octahedra, corners with two equivalent FeO6 octahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–53°. There are a spread of P–O bond distances ranging from 1.53–1.60 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Cd2+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cd2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Cd2+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Fe3+, one Cd2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Fe3+, one Cd2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Fe3+, one Cd2+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Fe3+, one Cd2+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to two Cd2+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to two Cd2+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the fourteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Cd2+ and one P5+ atom.