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6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on La2Hf2O7 by Materials Project

La2Hf2O7 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. La3+ is bonded to eight O2- atoms to form distorted LaO8 hexagonal bipyramids that share edges with six equivalent LaO8 hexagonal bipyramids and edges with six equivalent HfO6 octahedra. There are two shorter (2.34 Å) and six longer (2.65 Å) La–O bond lengths. Hf4+ is bonded to six equivalent O2- atoms to form HfO6 octahedra that share corners with six equivalent HfO6 octahedra and edges with six equivalent LaO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 49°. All Hf–O bond lengths are 2.10 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent La3+ atoms to form corner-sharing OLa4 tetrahedra. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent La3+ and two equivalent Hf4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2Hf2O7 by Materials Project

La2Hf2O7 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. La3+ is bonded in a distorted hexagonal planar geometry to six equivalent O2- atoms. All La–O bond lengths are 2.38 Å. Hf4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are six shorter (2.24 Å) and two longer (2.31 Å) Hf–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent La3+ and two equivalent Hf4+ atoms to form a mixture of edge and corner-sharing OLa2Hf2 tetrahedra. In the second O2- site, O2- is bonded to four equivalent Hf4+ atoms to form a mixture of edge and corner-sharing OHf4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2HfO5 by Materials Project

La2HfO5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of La–O bond distances ranging from 1.75–2.51 Å. In the second La3+ site, La3+ is bonded in a 1-coordinate geometry to four O2- atoms. There are a spread of La–O bond distances ranging from 1.95–2.54 Å. In the third La3+ site, La3+ is bonded in a 1-coordinate geometry to four O2- atoms. There are a spread of La–O bond distances ranging from 1.96–2.53 Å. In the fourth La3+ site, La3+ is bonded in a 2-coordinate geometry to four O2- atoms. There are a spread of La–O bond distances ranging from 1.76–2.53 Å. There are two inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded in a distorted square co-planar geometry to four O2- atoms. There are a spread of Hf–O bond distances ranging from 1.36–2.12 Å. In the second Hf4+ site, Hf4+ is bonded in a 2-coordinate geometry to four O2- atoms. There are two shorter (1.79 Å) and two longer (2.27 Å) Hf–O bond lengths. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one La3+ and one Hf4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two La3+ and one Hf4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two La3+ and one Hf4+ atom. In the fourth O2- site, O2- is bonded in a water-like geometry to one La3+ and one Hf4+ atom. In the fifth O2- site, O2- is bonded in a water-like geometry to one La3+ and one Hf4+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two La3+ and one Hf4+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two La3+ and one Hf4+ atom. In the eighth O2- site, O2- is bonded in an L-shaped geometry to two La3+ atoms. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one La3+ and one Hf4+ atom. In the tenth O2- site, O2- is bonded in a distorted L-shaped geometry to two La3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2HfO5 by Materials Project

La2HfO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded to seven O2- atoms to form distorted LaO7 hexagonal pyramids that share corners with three equivalent HfO5 trigonal bipyramids, edges with two equivalent LaO7 hexagonal pyramids, and edges with two equivalent HfO5 trigonal bipyramids. There are a spread of La–O bond distances ranging from 2.42–2.59 Å. In the second La3+ site, La3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of La–O bond distances ranging from 2.48–2.58 Å. Hf4+ is bonded to five O2- atoms to form distorted HfO5 trigonal bipyramids that share corners with three equivalent LaO7 hexagonal pyramids, corners with two equivalent HfO5 trigonal bipyramids, and edges with two equivalent LaO7 hexagonal pyramids. There are a spread of Hf–O bond distances ranging from 1.94–2.08 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four La3+ atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent La3+ and one Hf4+ atom. In the third O2- site, O2- is bonded to three La3+ and one Hf4+ atom to form OLa3Hf tetrahedra that share corners with eight OLa4 tetrahedra and edges with two equivalent OLa3Hf tetrahedra. In the fourth O2- site, O2- is bonded to three La3+ and one Hf4+ atom to form a mixture of distorted edge and corner-sharing OLa3Hf tetrahedra. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two La3+ and two equivalent Hf4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2HfO5 by Materials Project

La2HfO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded to six O2- atoms to form distorted LaO6 octahedra that share corners with two equivalent LaO6 octahedra, corners with four equivalent HfO6 octahedra, and edges with six LaO6 octahedra. The corner-sharing octahedra tilt angles range from 62–65°. There are a spread of La–O bond distances ranging from 2.45–2.48 Å. In the second La3+ site, La3+ is bonded to six O2- atoms to form LaO6 octahedra that share corners with four LaO6 octahedra, corners with four equivalent HfO6 octahedra, and edges with four LaO6 octahedra. The corner-sharing octahedra tilt angles range from 52–66°. There are a spread of La–O bond distances ranging from 2.34–2.51 Å. Hf4+ is bonded to six O2- atoms to form HfO6 octahedra that share corners with two equivalent HfO6 octahedra, corners with eight LaO6 octahedra, and edges with two equivalent HfO6 octahedra. The corner-sharing octahedra tilt angles range from 34–64°. There are a spread of Hf–O bond distances ranging from 2.03–2.36 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four La3+ atoms to form OLa4 tetrahedra that share corners with ten OLa4 tetrahedra and edges with three OLa3Hf tetrahedra. In the second O2- site, O2- is bonded in a 3-coordinate geometry to three equivalent Hf4+ atoms. In the third O2- site, O2- is bonded to three La3+ and one Hf4+ atom to form a mixture of distorted edge and corner-sharing OLa3Hf tetrahedra. In the fourth O2- site, O2- is bonded to three equivalent La3+ and one Hf4+ atom to form a mixture of distorted edge and corner-sharing OLa3Hf tetrahedra. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent La3+ and one Hf4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2Hf2O7 by Materials Project

La2Hf2O7 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are four inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of La–O bond distances ranging from 2.38–2.86 Å. In the second La3+ site, La3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of La–O bond distances ranging from 2.39–2.73 Å. In the third La3+ site, La3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of La–O bond distances ranging from 2.47–2.63 Å. In the fourth La3+ site, La3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of La–O bond distances ranging from 2.42–3.10 Å. There are four inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to six O2- atoms to form corner-sharing HfO6 octahedra. The corner-sharing octahedra tilt angles range from 29–38°. There are a spread of Hf–O bond distances ranging from 2.01–2.19 Å. In the second Hf4+ site, Hf4+ is bonded to six O2- atoms to form corner-sharing HfO6 octahedra. The corner-sharing octahedra tilt angles range from 23–38°. There are a spread of Hf–O bond distances ranging from 2.00–2.23 Å. In the third Hf4+ site, Hf4+ is bonded to six O2- atoms to form corner-sharing HfO6 octahedra. The corner-sharing octahedra tilt angles range from 29–41°. There are a spread of Hf–O bond distances ranging from 1.98–2.24 Å. In the fourth Hf4+ site, Hf4+ is bonded to six O2- atoms to form corner-sharing HfO6 octahedra. The corner-sharing octahedra tilt angles range from 23–41°. There are a spread of Hf–O bond distances ranging from 2.00–2.27 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded to two La3+ and two Hf4+ atoms to form distorted OLa2Hf2 tetrahedra that share corners with five OLa3Hf tetrahedra and an edgeedge with one OLa2Hf2 tetrahedra. In the second O2- site, O2- is bonded to three La3+ and one Hf4+ atom to form distorted OLa3Hf tetrahedra that share corners with five OLa2Hf2 tetrahedra and edges with four OLa3Hf tetrahedra. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two La3+ and two Hf4+ atoms. In the fourth O2- site, O2- is bonded in a distorted T-shaped geometry to one La3+ and two Hf4+ atoms. In the fifth O2- site, O2- is bonded to three La3+ and one Hf4+ atom to form distorted OLa3Hf tetrahedra that share corners with seven OLa2Hf2 tetrahedra and edges with three equivalent OLa3Hf tetrahedra. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to three La3+ and two equivalent Hf4+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two La3+ and two Hf4+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two La3+ and one Hf4+ atom. In the ninth O2- site, O2- is bonded to two La3+ and two Hf4+ atoms to form a mixture of distorted corner and edge-sharing OLa2Hf2 tetrahedra. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two La3+ and two Hf4+ atoms. In the eleventh O2- site, O2- is bonded to two La3+ and two Hf4+ atoms to form a mixture of distorted corner and edge-sharing OLa2Hf2 tetrahedra. In the twelfth O2- site, O2- is bonded to three La3+ and one Hf4+ atom to form a mixture of distorted corner and edge-sharing OLa3Hf tetrahedra. In the thirteenth O2- site, O2- is bonded in a 5-coordinate geometry to three La3+ and two equivalent Hf4+ atoms. In the fourteenth O2- site, O2- is bonded in a 2-coordinate geometry to two La3+ and two Hf4+ atoms.

36 MATERIALS SCIENCE↗