Materials Data on La3TaO7 by Materials Project

Abstract

La3TaO7 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. there are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.46 Å) and four longer (2.77 Å) La–O bond lengths. In the second La3+ site, La3+ is bonded to six O2- atoms to form distorted LaO6 octahedra that share corners with two equivalent LaO6 octahedra, corners with four equivalent TaO6 octahedra, and edges with two equivalent LaO6 octahedra. The corner-sharing octahedra tilt angles range from 58–69°. There are two shorter (2.35 Å) and four longer (2.48 Å) La–O bond lengths. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra and corners with eight equivalent LaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–58°. There are two shorter (1.98 Å) and four longer (2.02 Å) Ta–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three La3+ and one Ta5+ atom. In the third O2- site, O2- is bonded to four La3+ atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra.