Ca2CuO3 crystallizes in the orthorhombic Immm space group. Ca(1) is bonded to two equivalent O(1) and five equivalent O(2) atoms to form a mixture of distorted edge, corner, and face-sharing CaO7 pentagonal bipyramids. Cu(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) and two equivalent Cu(1) atoms to form OCa4Cu2 octahedra that share corners with two equivalent O(1)Ca4Cu2 octahedra, corners with twelve equivalent O(2)Ca5Cu octahedra, edges with two equivalent O(1)Ca4Cu2 octahedra, and faces with four equivalent O(2)Ca5Cu octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the second O site, O(2) is bonded to five equivalent Ca(1) and one Cu(1) atom to form OCa5Cu octahedra that share corners with five equivalent O(2)Ca5Cu octahedra, corners with six equivalent O(1)Ca4Cu2 octahedra, edges with eight equivalent O(2)Ca5Cu octahedra, and faces with two equivalent O(1)Ca4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°.
Ca2CuO3 crystallizes in the orthorhombic Immm space group. Ca(1) is bonded to two equivalent O(1) and five equivalent O(2) atoms to form a mixture of distorted edge, corner, and face-sharing CaO7 pentagonal bipyramids. Both Ca(1)-O(1) bond lengths are 2.43 Å. There is one shorter (2.32 Å) and four longer (2.50 Å) Ca(1)-O(2) bond lengths. Cu(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Cu(1)-O(1) bond lengths are 1.89 Å. Both Cu(1)-O(2) bond lengths are 1.94 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) and two equivalent Cu(1) atoms to form OCa4Cu2 octahedra that share corners with two equivalent O(1)Ca4Cu2 octahedra, corners with twelve equivalent O(2)Ca5Cu octahedra, edges with two equivalent O(1)Ca4Cu2 octahedra, and faces with four equivalent O(2)Ca5Cu octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the second O site, O(2) is bonded to five equivalent Ca(1) and one Cu(1) atom to form OCa5Cu octahedra that share corners with five equivalent O(2)Ca5Cu octahedra, corners with six equivalent O(1)Ca4Cu2 octahedra, edges with eight equivalent O(2)Ca5Cu octahedra, and faces with two equivalent O(1)Ca4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°.