Materials Data on Eu5Ta4O15 by Materials Project

Abstract

Eu5Ta4O15 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are three inequivalent Eu2+ sites. In the first Eu2+ site, Eu2+ is bonded to twelve O2- atoms to form EuO12 cuboctahedra that share corners with six equivalent EuO12 cuboctahedra and faces with eight TaO6 octahedra. There are six shorter (2.80 Å) and six longer (2.85 Å) Eu–O bond lengths. In the second Eu2+ site, Eu2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Eu–O bond distances ranging from 2.49–3.13 Å. In the third Eu2+ site, Eu2+ is bonded in a 9-coordinate geometry to nine equivalent O2- atoms. There are three shorter (2.50 Å) and six longer (2.89 Å) Eu–O bond lengths. 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 six TaO6 octahedra and faces with three equivalent EuO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are three shorter (1.98 Å) and three longer (2.04 Å) Ta–O bond lengths. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent TaO6 octahedra and a faceface with one EuO12 cuboctahedra. The corner-sharing octahedral tilt angles are 8°. There are three shorter (1.90 Å) and three longer (2.15 Å) Ta–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four Eu2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to three Eu2+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four Eu2+ and one Ta5+ atom.