K4OBr2 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(1) and five equivalent Br(1) atoms. In the second K site, K(2) is bonded in a distorted linear geometry to two equivalent O(1) and four equivalent Br(1) atoms. O(1) is bonded to two equivalent K(1) and four equivalent K(2) atoms to form corner-sharing OK6 octahedra. The corner-sharing octahedra are not tilted. Br(1) is bonded in a 9-coordinate geometry to four equivalent K(2) and five equivalent K(1) atoms.
K4OBr2 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(1) and five equivalent Br(1) atoms. The K(1)-O(1) bond length is 2.55 Å. There is one shorter (3.32 Å) and four longer (3.64 Å) K(1)-Br(1) bond lengths. In the second K site, K(2) is bonded in a distorted linear geometry to two equivalent O(1) and four equivalent Br(1) atoms. Both K(2)-O(1) bond lengths are 2.57 Å. All K(2)-Br(1) bond lengths are 3.50 Å. O(1) is bonded to two equivalent K(1) and four equivalent K(2) atoms to form corner-sharing OK6 octahedra. The corner-sharing octahedra are not tilted. Br(1) is bonded in a 9-coordinate geometry to four equivalent K(2) and five equivalent K(1) atoms.