Materials Data on K2EuTa5O15 by Materials Project

Abstract

K2EuTa5O15 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.86–3.24 Å. Eu3+ is bonded to twelve O2- atoms to form EuO12 cuboctahedra that share faces with two equivalent EuO12 cuboctahedra and faces with eight equivalent TaO6 octahedra. There are four shorter (2.65 Å) and eight longer (2.72 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 two equivalent EuO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 9–36°. There are a spread of Ta–O bond distances ranging from 1.92–2.05 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–31°. There is two shorter (1.98 Å) and four longer (2.00 Å) Ta–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two equivalent K1+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Eu3+, and two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+ and two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Eu3+ and two equivalent Ta5+ atoms.