Ba4CaCu2O6CO3 crystallizes in the orthorhombic Amm2 space group. Ba(1) is bonded to one O(2), one O(3), one O(5), one O(6), two equivalent O(1), and two equivalent O(4) atoms to form distorted BaO8 hexagonal bipyramids that share corners with eight equivalent Ba(1)O8 hexagonal bipyramids, edges with two equivalent Ba(1)O8 hexagonal bipyramids, faces with three equivalent Ba(1)O8 hexagonal bipyramids, and faces with two equivalent Ca(1)O6 octahedra. Ca(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form CaO6 octahedra that share faces with eight equivalent Ba(1)O8 hexagonal bipyramids. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a square co-planar geometry to one O(2), one O(3), and two equivalent O(4) atoms. In the second Cu site, Cu(2) is bonded in a linear geometry to two equivalent O(1) atoms. C(1) is bonded in a trigonal planar geometry to one O(6) and two equivalent O(5) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to four equivalent Ba(1), one Ca(1), and one Cu(2) atom. In the second O site, O(2) is bonded to four equivalent Ba(1), one Ca(1), and one Cu(1) atom to form a mixture of distorted face, corner, and edge-sharing OBa4CaCu octahedra. The corner-sharing octahedra are not tilted. In the third O site, O(3) is bonded to four equivalent Ba(1), one Ca(1), and one Cu(1) atom to form a mixture of distorted face, corner, and edge-sharing OBa4CaCu octahedra. The corner-sharing octahedra are not tilted. In the fourth O site, O(4) is bonded to four equivalent Ba(1), one Ca(1), and one Cu(1) atom to form a mixture of distorted face, corner, and edge-sharing OBa4CaCu octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one C(1) atom. In the sixth O site, O(6) is bonded in a single-bond geometry to four equivalent Ba(1) and one C(1) atom.
Ba4CaCu2O6CO3 crystallizes in the orthorhombic Amm2 space group. Ba(1) is bonded to one O(2), one O(3), one O(5), one O(6), two equivalent O(1), and two equivalent O(4) atoms to form distorted BaO8 hexagonal bipyramids that share corners with eight equivalent Ba(1)O8 hexagonal bipyramids, edges with two equivalent Ba(1)O8 hexagonal bipyramids, faces with three equivalent Ba(1)O8 hexagonal bipyramids, and faces with two equivalent Ca(1)O6 octahedra. The Ba(1)-O(2) bond length is 2.83 Å. The Ba(1)-O(3) bond length is 2.80 Å. The Ba(1)-O(5) bond length is 2.78 Å. The Ba(1)-O(6) bond length is 3.09 Å. There is one shorter (2.94 Å) and one longer (2.97 Å) Ba(1)-O(1) bond length. There is one shorter (2.84 Å) and one longer (2.88 Å) Ba(1)-O(4) bond length. Ca(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form CaO6 octahedra that share faces with eight equivalent Ba(1)O8 hexagonal bipyramids. The Ca(1)-O(2) bond length is 2.31 Å. The Ca(1)-O(3) bond length is 2.34 Å. Both Ca(1)-O(1) bond lengths are 2.34 Å. Both Ca(1)-O(4) bond lengths are 2.23 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a square co-planar geometry to one O(2), one O(3), and two equivalent O(4) atoms. The Cu(1)-O(2) bond length is 1.87 Å. The Cu(1)-O(3) bond length is 1.88 Å. Both Cu(1)-O(4) bond lengths are 1.84 Å. In the second Cu site, Cu(2) is bonded in a linear geometry to two equivalent O(1) atoms. Both Cu(2)-O(1) bond lengths are 1.82 Å. C(1) is bonded in a trigonal planar geometry to one O(6) and two equivalent O(5) atoms. The C(1)-O(6) bond length is 1.30 Å. Both C(1)-O(5) bond lengths are 1.30 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to four equivalent Ba(1), one Ca(1), and one Cu(2) atom. In the second O site, O(2) is bonded to four equivalent Ba(1), one Ca(1), and one Cu(1) atom to form a mixture of distorted face, corner, and edge-sharing OBa4CaCu octahedra. The corner-sharing octahedra are not tilted. In the third O site, O(3) is bonded to four equivalent Ba(1), one Ca(1), and one Cu(1) atom to form a mixture of distorted face, corner, and edge-sharing OBa4CaCu octahedra. The corner-sharing octahedra are not tilted. In the fourth O site, O(4) is bonded to four equivalent Ba(1), one Ca(1), and one Cu(1) atom to form a mixture of distorted face, corner, and edge-sharing OBa4CaCu octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one C(1) atom. In the sixth O site, O(6) is bonded in a single-bond geometry to four equivalent Ba(1) and one C(1) atom.