Materials Data on K3TaO8 by Materials Project
K3TaO8 crystallizes in the tetragonal I-42m space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded in a 4-coordinate geometry to four equivalent O atoms. All K–O bond lengths are 2.72 Å. In the second K site, K is bonded to eight O atoms to form KO8 hexagonal bipyramids that share corners with four equivalent TaO8 hexagonal bipyramids, corners with four equivalent OK3TaO trigonal bipyramids, and edges with two equivalent TaO8 hexagonal bipyramids. There are four shorter (2.82 Å) and four longer (2.88 Å) K–O bond lengths. Ta is bonded to eight O atoms to form distorted TaO8 hexagonal bipyramids that share corners with four equivalent KO8 hexagonal bipyramids, corners with four equivalent OK3TaO trigonal bipyramids, and edges with two equivalent KO8 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 to three K, one Ta, and one O atom to form distorted OK3TaO trigonal bipyramids that share a cornercorner with one KO8 hexagonal bipyramid, a cornercorner with one TaO8 hexagonal bipyramid, corners with ten equivalent OK3TaO trigonal bipyramids, and an edgeedge with one OK3TaO trigonal bipyramid. The O–O bond length is 1.51 Å. In the second O site, O is bonded in a 7-coordinate geometry to one K, one Ta, and one O atom.