DOI: 10.17188/1284163
title: Materials Data on Y2Ti2O7 by Materials Project

description: Y2Ti2O7 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are eight inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Y–O bond distances ranging from 2.26–2.88 Å. In the second Y3+ site, Y3+ is bonded to eight O2- atoms to form distorted YO8 hexagonal bipyramids that share a cornercorner with one TiO6 octahedra, an edgeedge with one YO8 hexagonal bipyramid, and edges with six TiO6 octahedra. The corner-sharing octahedral tilt angles are 67°. There are a spread of Y–O bond distances ranging from 2.20–2.75 Å. In the third Y3+ site, Y3+ is bonded to seven O2- atoms to form distorted YO7 hexagonal pyramids that share corners with four TiO6 octahedra and edges with four TiO6 octahedra. The corner-sharing octahedra tilt angles range from 53–68°. There are a spread of Y–O bond distances ranging from 2.15–2.60 Å. In the fourth Y3+ site, Y3+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Y–O bond distances ranging from 2.31–2.65 Å. In the fifth Y3+ site, Y3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are two shorter (2.17 Å) and four longer (2.43 Å) Y–O bond lengths. In the sixth Y3+ site, Y3+ is bonded to eight O2- atoms to form distorted YO8 hexagonal bipyramids that share edges with four YO8 hexagonal bipyramids and edges with six TiO6 octahedra. There are a spread of Y–O bond distances ranging from 2.20–2.52 Å. In the seventh Y3+ site, Y3+ is bonded to eight O2- atoms to form distorted YO8 hexagonal bipyramids that share edges with three YO8 hexagonal bipyramids and edges with six TiO6 octahedra. There are a spread of Y–O bond distances ranging from 2.20–2.55 Å. In the eighth Y3+ site, Y3+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Y–O bond distances ranging from 2.23–2.50 Å. There are seven inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share a cornercorner with one YO8 hexagonal bipyramid, corners with four equivalent TiO6 octahedra, and edges with two equivalent YO7 hexagonal pyramids. The corner-sharing octahedra tilt angles range from 45–50°. There are a spread of Ti–O bond distances ranging from 1.88–2.11 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share a cornercorner with one YO7 hexagonal pyramid, corners with six TiO6 octahedra, an edgeedge with one YO8 hexagonal bipyramid, and an edgeedge with one YO7 hexagonal pyramid. The corner-sharing octahedra tilt angles range from 36–50°. There are a spread of Ti–O bond distances ranging from 1.86–2.13 Å. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent YO7 hexagonal pyramids and corners with four equivalent TiO6 octahedra. The corner-sharing octahedral tilt angles are 48°. There are four shorter (1.98 Å) and two longer (2.06 Å) Ti–O bond lengths. In the fourth Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six TiO6 octahedra and edges with four YO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 47–50°. There are a spread of Ti–O bond distances ranging from 1.95–2.05 Å. In the fifth Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share a cornercorner with one YO7 hexagonal pyramid, corners with five TiO6 octahedra, and edges with two equivalent YO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 42–50°. There are a spread of Ti–O bond distances ranging from 1.92–2.17 Å. In the sixth Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six TiO6 octahedra and edges with four YO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 46–51°. There are a spread of Ti–O bond distances ranging from 1.95–2.03 Å. In the seventh Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six TiO6 octahedra and edges with four equivalent YO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 48°. There is four shorter (1.96 Å) and two longer (2.00 Å) Ti–O bond length. There are twenty inequivalent O2- sites. In the first O2- site, O2- is bonded to three Y3+ and one Ti4+ atom to form corner-sharing OY3Ti tetrahedra. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Y3+ and two Ti4+ atoms. In the third O2- site, O2- is bonded to three Y3+ and one Ti4+ atom to form OY3Ti tetrahedra that share corners with three OY3Ti tetrahedra and an edgeedge with one OY4 tetrahedra. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Y3+ and two Ti4+ atoms. In the fifth O2- site, O2- is bonded to three Y3+ and one Ti4+ atom to form a mixture of edge and corner-sharing OY3Ti tetrahedra. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Y3+ and two equivalent Ti4+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Y3+ and two equivalent Ti4+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to two Y3+ and two Ti4+ atoms. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to two Y3+ and two Ti4+ atoms. In the tenth O2- site, O2- is bonded to three Y3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing OY3Ti tetrahedra. In the eleventh O2- site, O2- is bonded to four Y3+ atoms to form a mixture of edge and corner-sharing OY4 tetrahedra. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to two Y3+ and two Ti4+ atoms. In the thirteenth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Y3+ and two Ti4+ atoms. In the fourteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Y3+ and two Ti4+ atoms. In the fifteenth O2- site, O2- is bonded to four Y3+ atoms to form corner-sharing OY4 tetrahedra. In the sixteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Y3+ and two equivalent Ti4+ atoms. In the seventeenth O2- site, O2- is bonded in a 4-coordinate geometry to two Y3+ and two Ti4+ atoms. In the eighteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Y3+ and two equivalent Ti4+ atoms. In the nineteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Y3+ and two Ti4+ atoms. In the twentieth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Y3+ and two Ti4+ atoms.