Materials Data on Ca3Cr6(FeO6)4 by Materials Project
Ca3Cr6(FeO6)4 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with six CrO4 tetrahedra, and corners with two equivalent CaO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 59°. There are two shorter (2.33 Å) and four longer (2.38 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded to five O2- atoms to form distorted CaO5 trigonal bipyramids that share a cornercorner with one CaO6 octahedra, corners with five CrO4 tetrahedra, and edges with two FeO6 octahedra. The corner-sharing octahedral tilt angles are 62°. There are a spread of Ca–O bond distances ranging from 2.25–2.35 Å. There are three inequivalent Cr5+ sites. In the first Cr5+ site, Cr5+ is bonded to four O2- atoms to form CrO4 tetrahedra that share a cornercorner with one CaO6 octahedra, corners with four FeO6 octahedra, and corners with two equivalent CaO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 21–64°. There are a spread of Cr–O bond distances ranging from 1.69–1.77 Å. In the second Cr5+ site, Cr5+ is bonded to four O2- atoms to form CrO4 tetrahedra that share a cornercorner with one CaO6 octahedra, corners with five FeO6 octahedra, and a cornercorner with one CaO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 36–55°. There are a spread of Cr–O bond distances ranging from 1.65–1.80 Å. In the third Cr5+ site, Cr5+ is bonded to four O2- atoms to form CrO4 tetrahedra that share a cornercorner with one CaO6 octahedra, corners with three FeO6 octahedra, and corners with two equivalent CaO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 23–60°. There are a spread of Cr–O bond distances ranging from 1.71–1.76 Å. There are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one CaO6 octahedra, corners with six CrO4 tetrahedra, an edgeedge with one FeO6 octahedra, and an edgeedge with one CaO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 59°. There are a spread of Fe–O bond distances ranging from 1.92–2.07 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six CrO4 tetrahedra, an edgeedge with one FeO6 octahedra, and an edgeedge with one CaO5 trigonal bipyramid. There are a spread of Fe–O bond distances ranging from 1.96–2.21 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Cr5+, and one Fe3+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr5+ and one Fe3+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one Cr5+ atom. In the fourth O2- site, O2- is bonded in a trigonal planar geometry to two Ca2+ and one Cr5+ atom. In the fifth O2- site, O2- is bonded in a trigonal planar geometry to one Ca2+, one Cr5+, and one Fe3+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Cr5+ and two equivalent Fe3+ atoms. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Cr5+, and one Fe3+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Cr5+, and one Fe3+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Cr5+, and one Fe3+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Cr5+ and two equivalent Fe3+ atoms. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr5+ and one Fe3+ atom. In the twelfth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr5+ and one Fe3+ atom.