DOI: 10.17188/1283193
title: Materials Data on Dy2Ti2O7 by Materials Project

description: Dy2Ti2O7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are eight inequivalent Dy3+ sites. In the first Dy3+ site, Dy3+ is bonded to seven O2- atoms to form distorted DyO7 pentagonal bipyramids that share a cornercorner with one DyO7 hexagonal pyramid, a cornercorner with one TiO6 octahedra, a cornercorner with one TiO6 pentagonal pyramid, an edgeedge with one DyO6 octahedra, and an edgeedge with one TiO6 octahedra. The corner-sharing octahedral tilt angles are 74°. There are a spread of Dy–O bond distances ranging from 2.29–2.54 Å. In the second Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Dy–O bond distances ranging from 2.25–2.78 Å. In the third Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to six O2- atoms. There are a spread of Dy–O bond distances ranging from 2.27–2.60 Å. In the fourth Dy3+ site, Dy3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Dy–O bond distances ranging from 2.20–2.53 Å. In the fifth Dy3+ site, Dy3+ is bonded to seven O2- atoms to form distorted DyO7 hexagonal pyramids that share a cornercorner with one DyO7 pentagonal bipyramid, a cornercorner with one TiO6 pentagonal pyramid, an edgeedge with one DyO8 hexagonal bipyramid, an edgeedge with one TiO6 octahedra, and an edgeedge with one TiO6 pentagonal pyramid. There are a spread of Dy–O bond distances ranging from 2.24–2.43 Å. In the sixth Dy3+ site, Dy3+ is bonded to six O2- atoms to form DyO6 octahedra that share corners with four TiO6 octahedra and edges with two equivalent DyO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Dy–O bond distances ranging from 2.19–2.24 Å. In the seventh Dy3+ site, Dy3+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Dy–O bond distances ranging from 2.37–2.71 Å. In the eighth Dy3+ site, Dy3+ is bonded to eight O2- atoms to form distorted DyO8 hexagonal bipyramids that share corners with two equivalent TiO6 octahedra, edges with two equivalent DyO7 hexagonal pyramids, edges with two equivalent TiO6 octahedra, and edges with two equivalent TiO6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 57°. There are a spread of Dy–O bond distances ranging from 2.19–2.65 Å. There are eight inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Ti–O bond distances ranging from 1.78–2.44 Å. In the second Ti4+ site, Ti4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ti–O bond distances ranging from 1.85–2.38 Å. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent DyO6 octahedra, corners with two equivalent TiO6 octahedra, and edges with two equivalent DyO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 28–60°. There are a spread of Ti–O bond distances ranging from 1.90–2.15 Å. In the fourth Ti4+ site, Ti4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ti–O bond distances ranging from 1.89–2.11 Å. In the fifth Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent DyO6 octahedra, corners with two equivalent TiO6 octahedra, and corners with two equivalent DyO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 28–56°. There are a spread of Ti–O bond distances ranging from 1.90–2.09 Å. In the sixth Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with two equivalent TiO6 pentagonal pyramids, and edges with two equivalent DyO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 55°. There are a spread of Ti–O bond distances ranging from 1.89–2.10 Å. In the seventh Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 pentagonal pyramids that share a cornercorner with one DyO7 hexagonal pyramid, corners with two TiO6 octahedra, a cornercorner with one DyO7 pentagonal bipyramid, an edgeedge with one DyO8 hexagonal bipyramid, and an edgeedge with one DyO7 hexagonal pyramid. The corner-sharing octahedra tilt angles range from 24–53°. There are a spread of Ti–O bond distances ranging from 1.87–2.09 Å. In the eighth Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent DyO8 hexagonal bipyramids, corners with two equivalent TiO6 octahedra, corners with two equivalent TiO6 pentagonal pyramids, and edges with two equivalent DyO7 hexagonal pyramids. The corner-sharing octahedral tilt angles are 55°. There are two shorter (1.96 Å) and four longer (2.08 Å) Ti–O bond lengths. There are twenty-one inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Dy3+ and one Ti4+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Dy3+ and two Ti4+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Dy3+ and two Ti4+ atoms. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Dy3+ and two Ti4+ atoms. In the fifth O2- site, O2- is bonded to two Dy3+ and two Ti4+ atoms to form distorted ODy2Ti2 trigonal pyramids that share corners with seven ODy3Ti tetrahedra and a cornercorner with one ODy2Ti2 trigonal pyramid. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Dy3+ and one Ti4+ atom. In the seventh O2- site, O2- is bonded to two Dy3+ and two Ti4+ atoms to form distorted ODy2Ti2 tetrahedra that share corners with four ODy3Ti tetrahedra, corners with two equivalent ODy2Ti2 trigonal pyramids, and an edgeedge with one ODy3Ti tetrahedra. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Dy3+ and one Ti4+ atom. In the ninth O2- site, O2- is bonded to two Dy3+ and two Ti4+ atoms to form distorted ODy2Ti2 tetrahedra that share corners with five ODy2Ti2 tetrahedra and edges with four ODy3Ti tetrahedra. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Dy3+ and two Ti4+ atoms. In the eleventh O2- site, O2- is bonded to three Dy3+ and one Ti4+ atom to form distorted ODy3Ti tetrahedra that share corners with three ODy2Ti2 tetrahedra, corners with three equivalent ODy2Ti2 trigonal pyramids, and edges with three ODy3Ti tetrahedra. In the twelfth O2- site, O2- is bonded to three Dy3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing ODy3Ti tetrahedra. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Dy3+ and two Ti4+ atoms. In the fourteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Dy3+ and two Ti4+ atoms. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Dy3+ and one Ti4+ atom. In the sixteenth O2- site, O2- is bonded to two Dy3+ and two Ti4+ atoms to form a mixture of distorted edge and corner-sharing ODy2Ti2 tetrahedra. In the seventeenth O2- site, O2- is bonded to two Dy3+ and two Ti4+ atoms to form ODy2Ti2 tetrahedra that share corners with seven ODy3Ti tetrahedra, a cornercorner with one ODy2Ti2 trigonal pyramid, and edges with three ODy2Ti2 tetrahedra. In the eighteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Dy3+ and two Ti4+ atoms. In the nineteenth O2- site, O2- is bonded to three Dy3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing ODy3Ti tetrahedra. In the twentieth O2- site, O2- is bonded to one Dy3+ and three Ti4+ atoms to form ODyTi3 tetrahedra that share corners with six ODy3Ti tetrahedra and edges with two ODy2Ti2 tetrahedra. In the twenty-first O2- site, O2- is bonded to three Dy3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing ODy3Ti tetrahedra.