Materials Data on K4Ta3NbO12 by Materials Project

Abstract

K4Ta3NbO12 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to twelve O2- atoms to form KO12 cuboctahedra that share corners with twelve KO12 cuboctahedra, faces with six KO12 cuboctahedra, a faceface with one NbO6 octahedra, and faces with seven TaO6 octahedra. All K–O bond lengths are 2.85 Å. In the second K1+ site, K1+ is bonded to twelve O2- atoms to form KO12 cuboctahedra that share corners with twelve KO12 cuboctahedra, faces with six KO12 cuboctahedra, faces with three equivalent NbO6 octahedra, and faces with five TaO6 octahedra. All K–O bond lengths are 2.85 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 three equivalent TaO6 octahedra, corners with three equivalent NbO6 octahedra, and faces with eight KO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ta–O bond lengths are 2.01 Å. In the second Ta5+ site, Ta5+ is bonded to six equivalent O2- atoms to form TaO6 octahedra that share corners with six equivalent TaO6 octahedra and faces with eight KO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ta–O bond lengths are 2.02 Å. Nb5+ is bonded to six equivalent O2- atoms to form NbO6 octahedra that share corners with six equivalent TaO6 octahedra and faces with eight KO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Nb–O bond lengths are 2.03 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four K1+ and two Ta5+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to four K1+, one Ta5+, and one Nb5+ atom.