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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ho2TiO5 by Materials Project

Ho2TiO5 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ho3+ is bonded to six O2- atoms to form distorted HoO6 pentagonal pyramids that share a cornercorner with one TiO6 octahedra, corners with three equivalent HoO6 pentagonal pyramids, edges with three equivalent TiO6 octahedra, and edges with three equivalent HoO6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 30°. There are a spread of Ho–O bond distances ranging from 2.18–2.38 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with two equivalent HoO6 pentagonal pyramids, and edges with six equivalent HoO6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 33°. There are a spread of Ti–O bond distances ranging from 1.88–2.12 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ho3+ and one Ti4+ atom. In the second O2- site, O2- is bonded to three equivalent Ho3+ and one Ti4+ atom to form distorted OHo3Ti trigonal pyramids that share a cornercorner with one OHo2Ti2 tetrahedra, corners with three equivalent OHo3Ti trigonal pyramids, edges with two equivalent OHo2Ti2 tetrahedra, and edges with two equivalent OHo3Ti trigonal pyramids. In the third O2- site, O2- is bonded to two equivalent Ho3+ and two equivalent Ti4+ atoms to form distorted OHo2Ti2 tetrahedra that share corners with two equivalent OHo2Ti2 tetrahedra, corners with two equivalent OHo3Ti trigonal pyramids, and edges with four equivalent OHo3Ti trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho2TiO5 by Materials Project

Ho2TiO5 crystallizes in the monoclinic C2/c 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 2.18–2.54 Å. Ti4+ is bonded to six O2- atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Ti–O bond distances ranging from 1.96–2.08 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 Ti4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three equivalent Ho3+ and one Ti4+ atom. In the third O2- site, O2- is bonded to two equivalent Ho3+ and two equivalent Ti4+ atoms to form distorted corner-sharing OHo2Ti2 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho2TiO5 by Materials Project

Ho2TiO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to seven O2- atoms to form distorted HoO7 hexagonal pyramids that share corners with two equivalent HoO7 hexagonal pyramids, corners with three equivalent TiO5 trigonal bipyramids, edges with five HoO7 hexagonal pyramids, and edges with two equivalent TiO5 trigonal bipyramids. There are a spread of Ho–O bond distances ranging from 2.27–2.38 Å. In the second Ho3+ site, Ho3+ is bonded to seven O2- atoms to form distorted HoO7 hexagonal pyramids that share corners with two equivalent HoO7 hexagonal pyramids, a cornercorner with one TiO5 trigonal bipyramid, edges with seven HoO7 hexagonal pyramids, and edges with two equivalent TiO5 trigonal bipyramids. There are a spread of Ho–O bond distances ranging from 2.34–2.36 Å. Ti4+ is bonded to five O2- atoms to form distorted TiO5 trigonal bipyramids that share corners with four HoO7 hexagonal pyramids, corners with two equivalent TiO5 trigonal bipyramids, and edges with four HoO7 hexagonal pyramids. There are a spread of Ti–O bond distances ranging from 1.79–1.97 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ho3+ atoms to form a mixture of edge and corner-sharing OHo4 tetrahedra. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ho3+ and one Ti4+ atom. In the third O2- site, O2- is bonded to three Ho3+ and one Ti4+ atom to form distorted OHo3Ti tetrahedra that share corners with nine OHo4 tetrahedra and edges with five OHo3Ti tetrahedra. In the fourth O2- site, O2- is bonded to two Ho3+ and two equivalent Ti4+ atoms to form distorted OHo2Ti2 tetrahedra that share corners with six OHo4 tetrahedra and edges with five OHo3Ti tetrahedra. In the fifth O2- site, O2- is bonded to three Ho3+ and one Ti4+ atom to form OHo3Ti tetrahedra that share corners with nine OHo4 tetrahedra and edges with four OHo3Ti tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho2TiO5 by Materials Project

Ho2TiO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six O2- atoms to form distorted HoO6 octahedra that share corners with two equivalent HoO6 octahedra, corners with four equivalent TiO6 octahedra, and edges with six HoO6 octahedra. The corner-sharing octahedra tilt angles range from 58–65°. There are a spread of Ho–O bond distances ranging from 2.28–2.32 Å. In the second Ho3+ site, Ho3+ is bonded to six O2- atoms to form HoO6 octahedra that share corners with four HoO6 octahedra, corners with four equivalent TiO6 octahedra, and edges with four HoO6 octahedra. The corner-sharing octahedra tilt angles range from 51–65°. There are a spread of Ho–O bond distances ranging from 2.20–2.34 Å. Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with eight HoO6 octahedra, and edges with two equivalent TiO6 octahedra. The corner-sharing octahedra tilt angles range from 34–65°. There are a spread of Ti–O bond distances ranging from 1.85–2.36 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ho3+ atoms to form OHo4 tetrahedra that share corners with ten OHo4 tetrahedra and edges with three OHo3Ti tetrahedra. In the second O2- site, O2- is bonded in a 2-coordinate geometry to three equivalent Ti4+ atoms. In the third O2- site, O2- is bonded to three Ho3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing OHo3Ti tetrahedra. In the fourth O2- site, O2- is bonded to three equivalent Ho3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing OHo3Ti tetrahedra. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ho3+ and one Ti4+ atom.

36 MATERIALS SCIENCE↗