Materials Data on KLuTa2O7 by Materials Project

Abstract

KLuTa2O7 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. K1+ is bonded to eight O2- atoms to form KO8 hexagonal bipyramids that share edges with two equivalent KO8 hexagonal bipyramids and edges with six TaO6 octahedra. There are a spread of K–O bond distances ranging from 2.56–2.76 Å. Lu3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Lu–O bond distances ranging from 2.08–2.72 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 six TaO6 octahedra and edges with two equivalent KO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 42°. There is two shorter (1.97 Å) and four longer (2.00 Å) Ta–O bond length. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and edges with four equivalent KO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 37–42°. There is two shorter (1.97 Å) and four longer (2.01 Å) Ta–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent K1+ and two equivalent Lu3+ atoms to form distorted corner-sharing OK2Lu2 tetrahedra. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Lu3+ and two equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+ and two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, one Lu3+, and two Ta5+ atoms.