Materials Data on CsNa7Ta8O24 by Materials Project

Abstract

CsNa7Ta8O24 is (Cubic) Perovskite-derived structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Cs1+ is bonded to twelve equivalent O2- atoms to form CsO12 cuboctahedra that share corners with twelve equivalent NaO12 cuboctahedra, faces with six equivalent NaO12 cuboctahedra, and faces with eight equivalent TaO6 octahedra. All Cs–O bond lengths are 2.91 Å. There are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to twelve O2- atoms to form NaO12 cuboctahedra that share corners with twelve NaO12 cuboctahedra, faces with two equivalent CsO12 cuboctahedra, faces with four equivalent NaO12 cuboctahedra, and faces with eight equivalent TaO6 octahedra. There are eight shorter (2.83 Å) and four longer (2.85 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded to twelve O2- atoms to form NaO12 cuboctahedra that share corners with four equivalent CsO12 cuboctahedra, corners with eight equivalent NaO12 cuboctahedra, faces with six NaO12 cuboctahedra, and faces with eight equivalent TaO6 octahedra. There are four shorter (2.75 Å) and eight longer (2.83 Å) Na–O bond lengths. In the third Na1+ site, Na1+ is bonded to twelve equivalent O2- atoms to form NaO12 cuboctahedra that share corners with twelve equivalent NaO12 cuboctahedra, faces with six equivalent NaO12 cuboctahedra, and faces with eight equivalent TaO6 octahedra. All Na–O bond lengths are 2.81 Å. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six equivalent TaO6 octahedra, a faceface with one CsO12 cuboctahedra, and faces with seven NaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are three shorter (1.99 Å) and three longer (2.02 Å) Ta–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to one Cs1+, three Na1+, and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to four Na1+ and two equivalent Ta5+ atoms.