Ca(CuO2)2 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form distorted CaO6 pentagonal pyramids that share corners with six equivalent Cu(1)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with four equivalent Cu(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-17°. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(3) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form CuO6 octahedra that share corners with three equivalent Ca(1)O6 pentagonal pyramids, edges with two equivalent Cu(1)O6 octahedra, edges with four equivalent Cu(2)O6 octahedra, and  an edgeedge with one Ca(1)O6 pentagonal pyramid. In the second Cu site, Cu(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CuO6 octahedra that share edges with two equivalent Cu(2)O6 octahedra, edges with four equivalent Cu(1)O6 octahedra, and edges with two equivalent Ca(1)O6 pentagonal pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Ca(1), one Cu(1), and two equivalent Cu(2) atoms. In the second O site, O(2) is bonded to one Ca(2), one Cu(1), and two equivalent Cu(2) atoms to form OCaCu3 trigonal pyramids that share corners with four equivalent O(3)Ca2Cu3 trigonal bipyramids, corners with three equivalent O(2)CaCu3 trigonal pyramids, and edges with four equivalent O(3)Ca2Cu3 trigonal bipyramids. In the third O site, O(3) is bonded to one Ca(1), one Ca(2), one Cu(2), and two equivalent Cu(1) atoms to form OCa2Cu3 trigonal bipyramids that share corners with five equivalent O(3)Ca2Cu3 trigonal bipyramids, corners with two equivalent O(2)CaCu3 trigonal pyramids, edges with four equivalent O(3)Ca2Cu3 trigonal bipyramids, and edges with two equivalent O(2)CaCu3 trigonal pyramids.
Ca(CuO2)2 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form distorted CaO6 pentagonal pyramids that share corners with six equivalent Cu(1)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with four equivalent Cu(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-17°. Both Ca(1)-O(1) bond lengths are 2.29 Å. All Ca(1)-O(3) bond lengths are 2.41 Å. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(3) atoms. Both Ca(2)-O(2) bond lengths are 2.31 Å. All Ca(2)-O(3) bond lengths are 2.40 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form CuO6 octahedra that share corners with three equivalent Ca(1)O6 pentagonal pyramids, edges with two equivalent Cu(1)O6 octahedra, edges with four equivalent Cu(2)O6 octahedra, and  an edgeedge with one Ca(1)O6 pentagonal pyramid. The Cu(1)-O(1) bond length is 1.97 Å. The Cu(1)-O(2) bond length is 2.02 Å. There are two shorter (2.02 Å) and two longer (2.09 Å) Cu(1)-O(3) bond lengths. In the second Cu site, Cu(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CuO6 octahedra that share edges with two equivalent Cu(2)O6 octahedra, edges with four equivalent Cu(1)O6 octahedra, and edges with two equivalent Ca(1)O6 pentagonal pyramids. Both Cu(2)-O(1) bond lengths are 2.01 Å. Both Cu(2)-O(2) bond lengths are 1.99 Å. Both Cu(2)-O(3) bond lengths are 2.06 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Ca(1), one Cu(1), and two equivalent Cu(2) atoms. In the second O site, O(2) is bonded to one Ca(2), one Cu(1), and two equivalent Cu(2) atoms to form OCaCu3 trigonal pyramids that share corners with four equivalent O(3)Ca2Cu3 trigonal bipyramids, corners with three equivalent O(2)CaCu3 trigonal pyramids, and edges with four equivalent O(3)Ca2Cu3 trigonal bipyramids. In the third O site, O(3) is bonded to one Ca(1), one Ca(2), one Cu(2), and two equivalent Cu(1) atoms to form OCa2Cu3 trigonal bipyramids that share corners with five equivalent O(3)Ca2Cu3 trigonal bipyramids, corners with two equivalent O(2)CaCu3 trigonal pyramids, edges with four equivalent O(3)Ca2Cu3 trigonal bipyramids, and edges with two equivalent O(2)CaCu3 trigonal pyramids.