Ba2Co2O5 crystallizes in the orthorhombic Ima2 space group. Ba(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted CoO6 octahedra that share corners with four equivalent Co(1)O6 octahedra and corners with two equivalent Co(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 2°. In the second Co site, Co(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form CoO4 tetrahedra that share corners with two equivalent Co(1)O6 octahedra and corners with two equivalent Co(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 20°. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1) and two equivalent Co(1) atoms to form a mixture of distorted edge, face, and corner-sharing OBa4Co2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Ba(1), one Co(1), and one Co(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1) and two equivalent Co(2) atoms.
Ba2Co2O5 crystallizes in the orthorhombic Ima2 space group. Ba(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. The Ba(1)-O(3) bond length is 2.69 Å. There are a spread of Ba(1)-O(1) bond distances ranging from 2.76-2.82 Å. There are a spread of Ba(1)-O(2) bond distances ranging from 2.80-3.07 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted CoO6 octahedra that share corners with four equivalent Co(1)O6 octahedra and corners with two equivalent Co(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 2°. Both Co(1)-O(2) bond lengths are 2.66 Å. All Co(1)-O(1) bond lengths are 2.01 Å. In the second Co site, Co(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form CoO4 tetrahedra that share corners with two equivalent Co(1)O6 octahedra and corners with two equivalent Co(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 20°. Both Co(2)-O(2) bond lengths are 1.78 Å. There is one shorter (1.89 Å) and one longer (1.92 Å) Co(2)-O(3) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1) and two equivalent Co(1) atoms to form a mixture of distorted edge, face, and corner-sharing OBa4Co2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Ba(1), one Co(1), and one Co(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1) and two equivalent Co(2) atoms.