Materials Data on Rb3TaO8 by Materials Project
Rb3TaO8 crystallizes in the tetragonal I-42m space group. The structure is three-dimensional. there are two inequivalent Rb sites. In the first Rb site, Rb is bonded to eight O atoms to form RbO8 hexagonal bipyramids that share corners with four equivalent TaO8 hexagonal bipyramids, corners with four equivalent ORb3TaO trigonal bipyramids, and edges with two equivalent TaO8 hexagonal bipyramids. There are four shorter (2.98 Å) and four longer (3.01 Å) Rb–O bond lengths. In the second Rb site, Rb is bonded in a 4-coordinate geometry to twelve O atoms. There are a spread of Rb–O bond distances ranging from 2.86–3.41 Å. Ta is bonded to eight O atoms to form distorted TaO8 hexagonal bipyramids that share corners with four equivalent RbO8 hexagonal bipyramids, corners with four equivalent ORb3TaO trigonal bipyramids, and edges with two equivalent RbO8 hexagonal bipyramids. There are four shorter (2.03 Å) and four longer (2.08 Å) Ta–O bond lengths. There are two inequivalent O sites. In the first O site, O is bonded in a 1-coordinate geometry to five Rb, one Ta, and one O atom. The O–O bond length is 1.51 Å. In the second O site, O is bonded to three Rb, one Ta, and one O atom to form distorted ORb3TaO trigonal bipyramids that share a cornercorner with one RbO8 hexagonal bipyramid, a cornercorner with one TaO8 hexagonal bipyramid, corners with ten equivalent ORb3TaO trigonal bipyramids, and an edgeedge with one ORb3TaO trigonal bipyramid.