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DOE OSTI2020

Materials Data on Ho2Ge2O7 by Materials Project

Ho2Ge2O7 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ho3+ is bonded to six O2- atoms to form distorted HoO6 pentagonal pyramids that share corners with six equivalent GeO4 tetrahedra and edges with three equivalent HoO6 pentagonal pyramids. There are a spread of Ho–O bond distances ranging from 2.24–2.32 Å. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with six equivalent HoO6 pentagonal pyramids and a cornercorner with one GeO4 tetrahedra. All Ge–O bond lengths are 1.77 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ho3+ and one Ge4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ho3+ and one Ge4+ atom. In the third O2- site, O2- is bonded in a linear geometry to two equivalent Ge4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho2Ge2O5 by Materials Project

Ho2Ge2O5 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Ho–O bond lengths are 2.56 Å. In the second Ho3+ site, Ho3+ is bonded to twelve O2- atoms to form HoO12 cuboctahedra that share corners with four equivalent HoO12 cuboctahedra, faces with four equivalent HoO12 cuboctahedra, and faces with eight equivalent GeO5 square pyramids. There are eight shorter (2.72 Å) and four longer (2.90 Å) Ho–O bond lengths. Ge2+ is bonded to five O2- atoms to form GeO5 square pyramids that share corners with five equivalent GeO5 square pyramids and faces with four equivalent HoO12 cuboctahedra. There is one shorter (1.90 Å) and four longer (2.05 Å) Ge–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ho3+ and two equivalent Ge2+ atoms to form a mixture of distorted face, edge, and corner-sharing OHo4Ge2 octahedra. The corner-sharing octahedra tilt angles range from 0–69°. In the second O2- site, O2- is bonded in a linear geometry to four equivalent Ho3+ and two equivalent Ge2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HoGeO3 by Materials Project

HoGeO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ho3+ is bonded to twelve equivalent O2- atoms to form HoO12 cuboctahedra that share corners with twelve equivalent HoO12 cuboctahedra, faces with six equivalent HoO12 cuboctahedra, and faces with eight equivalent GeO6 octahedra. All Ho–O bond lengths are 2.76 Å. Ge3+ is bonded to six equivalent O2- atoms to form GeO6 octahedra that share corners with six equivalent GeO6 octahedra and faces with eight equivalent HoO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ge–O bond lengths are 1.95 Å. O2- is bonded in a distorted linear geometry to four equivalent Ho3+ and two equivalent Ge3+ atoms.

36 MATERIALS SCIENCE↗