Materials Data on K3NbO8 by Materials Project
K3NbO8 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 NbO8 hexagonal bipyramids, corners with four equivalent OK3NbO trigonal bipyramids, and edges with two equivalent NbO8 hexagonal bipyramids. There are four shorter (2.82 Å) and four longer (2.88 Å) K–O bond lengths. Nb is bonded to eight O atoms to form distorted NbO8 hexagonal bipyramids that share corners with four equivalent KO8 hexagonal bipyramids, corners with four equivalent OK3NbO trigonal bipyramids, and edges with two equivalent KO8 hexagonal bipyramids. There are four shorter (2.04 Å) and four longer (2.09 Å) Nb–O bond lengths. There are two inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to one K, one Nb, and one O atom. The O–O bond length is 1.50 Å. In the second O site, O is bonded to three K, one Nb, and one O atom to form distorted OK3NbO trigonal bipyramids that share a cornercorner with one KO8 hexagonal bipyramid, a cornercorner with one NbO8 hexagonal bipyramid, corners with ten equivalent OK3NbO trigonal bipyramids, and an edgeedge with one OK3NbO trigonal bipyramid.