Materials Data on Eu2Ta2O7 by Materials Project

Abstract

Eu2Ta2O7 is Pb (Zr_0.50 Ti_0.48) O_3-like structured and crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Eu2+ sites. In the first Eu2+ site, Eu2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Eu–O bond distances ranging from 2.44–2.97 Å. In the second Eu2+ site, Eu2+ is bonded to twelve O2- atoms to form distorted EuO12 cuboctahedra that share corners with six equivalent EuO12 cuboctahedra, faces with four equivalent EuO12 cuboctahedra, and faces with eight TaO6 octahedra. There are a spread of Eu–O bond distances ranging from 2.53–3.01 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with four TaO6 octahedra and faces with two equivalent EuO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 12–32°. There are a spread of Ta–O bond distances ranging from 1.87–2.24 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with six equivalent EuO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 9–32°. There are a spread of Ta–O bond distances ranging from 1.88–2.18 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Eu2+ and two Ta5+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three equivalent Eu2+ and one Ta5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Eu2+ and two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Eu2+ and two Ta5+ atoms. In the fifth O2- site, O2- is bonded to three equivalent Eu2+ and one Ta5+ atom to form corner-sharing OEu3Ta tetrahedra. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Eu2+ and two equivalent Ta5+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to three equivalent Eu2+ and two equivalent Ta5+ atoms.