Materials Data on K4BaU3O12 by Materials Project

Abstract

BaK4U3O12 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 six equivalent O2- atoms to form KO6 octahedra that share corners with six equivalent UO6 octahedra, faces with two equivalent BaO12 cuboctahedra, and faces with six equivalent KO12 cuboctahedra. The corner-sharing octahedral tilt angles are 4°. All K–O bond lengths are 2.52 Å. In the second K1+ site, K1+ is bonded to twelve O2- atoms to form KO12 cuboctahedra that share corners with four equivalent BaO12 cuboctahedra, corners with eight equivalent KO12 cuboctahedra, faces with two equivalent BaO12 cuboctahedra, faces with four equivalent KO12 cuboctahedra, faces with two equivalent KO6 octahedra, and faces with six equivalent UO6 octahedra. There are a spread of K–O bond distances ranging from 3.13–3.24 Å. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve equivalent KO12 cuboctahedra, faces with six equivalent KO12 cuboctahedra, faces with two equivalent KO6 octahedra, and faces with six equivalent UO6 octahedra. There are six shorter (3.05 Å) and six longer (3.08 Å) Ba–O bond lengths. U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent KO6 octahedra, corners with four equivalent UO6 octahedra, faces with two equivalent BaO12 cuboctahedra, and faces with six equivalent KO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 3–4°. There are two shorter (1.91 Å) and four longer (2.22 Å) U–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to three equivalent K1+, one Ba2+, and two equivalent U6+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four K1+, one Ba2+, and one U6+ atom.