Materials Data on K3CrO8 by Materials Project
K3CrO8 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 twelve O atoms. There are a spread of K–O bond distances ranging from 2.71–3.21 Å. In the second K site, K is bonded to eight O atoms to form KO8 hexagonal bipyramids that share corners with four equivalent CrO8 hexagonal bipyramids, corners with four equivalent OK3CrO trigonal bipyramids, and edges with two equivalent CrO8 hexagonal bipyramids. There are four shorter (2.83 Å) and four longer (2.84 Å) K–O bond lengths. Cr is bonded to eight O atoms to form distorted CrO8 hexagonal bipyramids that share corners with four equivalent KO8 hexagonal bipyramids, corners with four equivalent OK3CrO trigonal bipyramids, and edges with two equivalent KO8 hexagonal bipyramids. There is four shorter (1.91 Å) and four longer (1.99 Å) Cr–O bond length. There are two inequivalent O sites. In the first O site, O is bonded in a 1-coordinate geometry to five K, one Cr, and one O atom. The O–O bond length is 1.45 Å. In the second O site, O is bonded to three K, one Cr, and one O atom to form distorted OK3CrO trigonal bipyramids that share a cornercorner with one KO8 hexagonal bipyramid, a cornercorner with one CrO8 hexagonal bipyramid, corners with ten equivalent OK3CrO trigonal bipyramids, and an edgeedge with one OK3CrO trigonal bipyramid.