Materials Data on Y2HfO5 by Materials Project

Abstract

Y2HfO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Y–O bond distances ranging from 2.29–2.62 Å. In the second Y3+ site, Y3+ is bonded to six O2- atoms to form YO6 octahedra that share corners with two equivalent YO6 octahedra, corners with four equivalent HfO6 octahedra, and edges with two equivalent YO6 octahedra. The corner-sharing octahedra tilt angles range from 54–64°. There are a spread of Y–O bond distances ranging from 2.21–2.40 Å. Hf4+ is bonded to six O2- atoms to form HfO6 octahedra that share corners with two equivalent HfO6 octahedra, corners with four equivalent YO6 octahedra, and edges with two equivalent HfO6 octahedra. The corner-sharing octahedra tilt angles range from 36–64°. There are a spread of Hf–O bond distances ranging from 1.99–2.30 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four Y3+ atoms to form OY4 tetrahedra that share corners with ten OY4 tetrahedra and edges with three OY3Hf 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 Y3+ and one Hf4+ atom to form a mixture of distorted edge and corner-sharing OY3Hf tetrahedra. In the fourth O2- site, O2- is bonded to three equivalent Y3+ and one Hf4+ atom to form a mixture of edge and corner-sharing OY3Hf tetrahedra. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Y3+ and one Hf4+ atom.