Materials Data on HoFeGe2O7 by Materials Project
HoFeGe2O7 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Ho3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ho–O bond distances ranging from 2.22–2.43 Å. Fe3+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with four GeO4 tetrahedra and an edgeedge with one FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.99–2.16 Å. There are four inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with four equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 45–54°. There are a spread of Ge–O bond distances ranging from 1.78–1.80 Å. In the second Ge4+ site, Ge4+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Ge–O bond distances ranging from 1.75–2.37 Å. In the third Ge4+ site, Ge4+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Ge–O bond distances ranging from 1.75–2.40 Å. In the fourth Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with four equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 45–54°. There are a spread of Ge–O bond distances ranging from 1.78–1.80 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ho3+, one Fe3+, and one Ge4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ho3+, one Fe3+, and one Ge4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+, one Fe3+, and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ge4+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ge4+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Fe3+ and two Ge4+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ho3+ and one Ge4+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ho3+ and one Ge4+ atom. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Fe3+ and two Ge4+ atoms. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+, one Fe3+, and one Ge4+ atom.