Materials Data on K2RbTbV2O8 by Materials Project
RbK2TbV2O8 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Rb1+ is bonded to twelve O2- atoms to form RbO12 cuboctahedra that share edges with six equivalent RbO12 cuboctahedra, edges with six equivalent VO4 tetrahedra, and faces with two equivalent TbO6 octahedra. There are six shorter (3.15 Å) and six longer (3.50 Å) Rb–O bond lengths. K1+ is bonded in a 1-coordinate geometry to ten O2- atoms. There are a spread of K–O bond distances ranging from 2.62–3.34 Å. Tb3+ is bonded to six equivalent O2- atoms to form TbO6 octahedra that share corners with six equivalent VO4 tetrahedra and faces with two equivalent RbO12 cuboctahedra. All Tb–O bond lengths are 2.28 Å. V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share corners with three equivalent TbO6 octahedra and edges with three equivalent RbO12 cuboctahedra. The corner-sharing octahedral tilt angles are 16°. There is one shorter (1.68 Å) and three longer (1.77 Å) V–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+, three equivalent K1+, one Tb3+, and one V5+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to three equivalent Rb1+, one K1+, and one V5+ atom.