BaKFeO3 crystallizes in the orthorhombic Cmce space group. K(1) is bonded in a 5-coordinate geometry to two equivalent O(3) and three equivalent O(2) atoms. Ba(1) is bonded to two equivalent O(1), two equivalent O(2), and three equivalent O(3) atoms to form distorted BaO7 pentagonal bipyramids that share corners with four equivalent Ba(1)O7 pentagonal bipyramids,  a cornercorner with one Fe(1)O4 tetrahedra, edges with three equivalent Ba(1)O7 pentagonal bipyramids, and edges with four equivalent Fe(1)O4 tetrahedra. Fe(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form FeO4 tetrahedra that share  a cornercorner with one Ba(1)O7 pentagonal bipyramid, corners with two equivalent Fe(1)O4 tetrahedra, and edges with four equivalent Ba(1)O7 pentagonal bipyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(1) and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded to three equivalent K(1), two equivalent Ba(1), and one Fe(1) atom to form distorted OK3Ba2Fe octahedra that share corners with two equivalent O(2)K3Ba2Fe octahedra, corners with three equivalent O(3)K2Ba3Fe octahedra, edges with three equivalent O(2)K3Ba2Fe octahedra, and edges with five equivalent O(3)K2Ba3Fe octahedra. The corner-sharing octahedral tilt angles range from 16-58°. In the third O site, O(3) is bonded to two equivalent K(1), three equivalent Ba(1), and one Fe(1) atom to form distorted OK2Ba3Fe octahedra that share corners with two equivalent O(3)K2Ba3Fe octahedra, corners with three equivalent O(2)K3Ba2Fe octahedra, edges with three equivalent O(3)K2Ba3Fe octahedra, and edges with five equivalent O(2)K3Ba2Fe octahedra. The corner-sharing octahedral tilt angles range from 21-58°.
BaKFeO3 crystallizes in the orthorhombic Cmce space group. K(1) is bonded in a 5-coordinate geometry to two equivalent O(3) and three equivalent O(2) atoms. There is one shorter (2.82 Å) and one longer (2.86 Å) K(1)-O(3) bond length. There are two shorter (3.00 Å) and one longer (3.08 Å) K(1)-O(2) bond length. Ba(1) is bonded to two equivalent O(1), two equivalent O(2), and three equivalent O(3) atoms to form distorted BaO7 pentagonal bipyramids that share corners with four equivalent Ba(1)O7 pentagonal bipyramids,  a cornercorner with one Fe(1)O4 tetrahedra, edges with three equivalent Ba(1)O7 pentagonal bipyramids, and edges with four equivalent Fe(1)O4 tetrahedra. Both Ba(1)-O(1) bond lengths are 2.82 Å. There is one shorter (2.63 Å) and one longer (2.77 Å) Ba(1)-O(2) bond length. There is one shorter (2.75 Å) and two longer (3.02 Å) Ba(1)-O(3) bond lengths. Fe(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form FeO4 tetrahedra that share  a cornercorner with one Ba(1)O7 pentagonal bipyramid, corners with two equivalent Fe(1)O4 tetrahedra, and edges with four equivalent Ba(1)O7 pentagonal bipyramids. The Fe(1)-O(2) bond length is 1.88 Å. The Fe(1)-O(3) bond length is 1.89 Å. Both Fe(1)-O(1) bond lengths are 1.92 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(1) and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded to three equivalent K(1), two equivalent Ba(1), and one Fe(1) atom to form distorted OK3Ba2Fe octahedra that share corners with two equivalent O(2)K3Ba2Fe octahedra, corners with three equivalent O(3)K2Ba3Fe octahedra, edges with three equivalent O(2)K3Ba2Fe octahedra, and edges with five equivalent O(3)K2Ba3Fe octahedra. The corner-sharing octahedral tilt angles range from 16-58°. In the third O site, O(3) is bonded to two equivalent K(1), three equivalent Ba(1), and one Fe(1) atom to form distorted OK2Ba3Fe octahedra that share corners with two equivalent O(3)K2Ba3Fe octahedra, corners with three equivalent O(2)K3Ba2Fe octahedra, edges with three equivalent O(3)K2Ba3Fe octahedra, and edges with five equivalent O(2)K3Ba2Fe octahedra. The corner-sharing octahedral tilt angles range from 21-58°.