SrCa(CuO2)2 crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(1), and four equivalent O(4) atoms. Ca(1) is bonded in a 7-coordinate geometry to one O(4), 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 in a square co-planar geometry to one O(1), one O(3), and two equivalent O(2) atoms. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to one O(2), one O(4), and two equivalent O(1) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), one Cu(1), and two equivalent Cu(2) atoms to form OSr2Cu3 trigonal bipyramids that share corners with three equivalent O(3)SrCa4Cu octahedra, corners with four equivalent O(4)Sr4CaCu octahedra, corners with four equivalent O(1)Sr2Cu3 trigonal bipyramids, edges with two equivalent O(2)Ca2Cu3 trigonal bipyramids, and faces with two equivalent O(4)Sr4CaCu octahedra. The corner-sharing octahedral tilt angles range from 0-59°. In the second O site, O(2) is bonded to two equivalent Ca(1), one Cu(2), and two equivalent Cu(1) atoms to form OCa2Cu3 trigonal bipyramids that share corners with three equivalent O(4)Sr4CaCu octahedra, corners with four equivalent O(3)SrCa4Cu octahedra, corners with four equivalent O(2)Ca2Cu3 trigonal bipyramids, edges with two equivalent O(1)Sr2Cu3 trigonal bipyramids, and faces with two equivalent O(3)SrCa4Cu octahedra. The corner-sharing octahedral tilt angles range from 0-59°. In the third O site, O(3) is bonded to one Sr(1), four equivalent Ca(1), and one Cu(1) atom to form distorted OSrCa4Cu octahedra that share corners with four equivalent O(3)SrCa4Cu octahedra, corners with three equivalent O(1)Sr2Cu3 trigonal bipyramids, corners with four equivalent O(2)Ca2Cu3 trigonal bipyramids, edges with four equivalent O(4)Sr4CaCu octahedra, edges with four equivalent O(3)SrCa4Cu octahedra, and faces with two equivalent O(2)Ca2Cu3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 8°. In the fourth O site, O(4) is bonded to four equivalent Sr(1), one Ca(1), and one Cu(2) atom to form OSr4CaCu octahedra that share corners with four equivalent O(4)Sr4CaCu octahedra, corners with three equivalent O(2)Ca2Cu3 trigonal bipyramids, corners with four equivalent O(1)Sr2Cu3 trigonal bipyramids, edges with four equivalent O(4)Sr4CaCu octahedra, edges with four equivalent O(3)SrCa4Cu octahedra, and faces with two equivalent O(1)Sr2Cu3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 10°.
SrCa(CuO2)2 crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(1), and four equivalent O(4) atoms. The Sr(1)-O(3) bond length is 2.42 Å. Both Sr(1)-O(1) bond lengths are 2.55 Å. All Sr(1)-O(4) bond lengths are 2.65 Å. Ca(1) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(2), and four equivalent O(3) atoms. The Ca(1)-O(4) bond length is 2.38 Å. Both Ca(1)-O(2) bond lengths are 2.49 Å. All Ca(1)-O(3) bond lengths are 2.64 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(1), one O(3), and two equivalent O(2) atoms. The Cu(1)-O(1) bond length is 1.90 Å. The Cu(1)-O(3) bond length is 1.88 Å. Both Cu(1)-O(2) bond lengths are 1.97 Å. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to one O(2), one O(4), and two equivalent O(1) atoms. The Cu(2)-O(2) bond length is 1.95 Å. The Cu(2)-O(4) bond length is 1.96 Å. Both Cu(2)-O(1) bond lengths are 1.97 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), one Cu(1), and two equivalent Cu(2) atoms to form OSr2Cu3 trigonal bipyramids that share corners with three equivalent O(3)SrCa4Cu octahedra, corners with four equivalent O(4)Sr4CaCu octahedra, corners with four equivalent O(1)Sr2Cu3 trigonal bipyramids, edges with two equivalent O(2)Ca2Cu3 trigonal bipyramids, and faces with two equivalent O(4)Sr4CaCu octahedra. The corner-sharing octahedral tilt angles range from 0-59°. In the second O site, O(2) is bonded to two equivalent Ca(1), one Cu(2), and two equivalent Cu(1) atoms to form OCa2Cu3 trigonal bipyramids that share corners with three equivalent O(4)Sr4CaCu octahedra, corners with four equivalent O(3)SrCa4Cu octahedra, corners with four equivalent O(2)Ca2Cu3 trigonal bipyramids, edges with two equivalent O(1)Sr2Cu3 trigonal bipyramids, and faces with two equivalent O(3)SrCa4Cu octahedra. The corner-sharing octahedral tilt angles range from 0-59°. In the third O site, O(3) is bonded to one Sr(1), four equivalent Ca(1), and one Cu(1) atom to form distorted OSrCa4Cu octahedra that share corners with four equivalent O(3)SrCa4Cu octahedra, corners with three equivalent O(1)Sr2Cu3 trigonal bipyramids, corners with four equivalent O(2)Ca2Cu3 trigonal bipyramids, edges with four equivalent O(4)Sr4CaCu octahedra, edges with four equivalent O(3)SrCa4Cu octahedra, and faces with two equivalent O(2)Ca2Cu3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 8°. In the fourth O site, O(4) is bonded to four equivalent Sr(1), one Ca(1), and one Cu(2) atom to form OSr4CaCu octahedra that share corners with four equivalent O(4)Sr4CaCu octahedra, corners with three equivalent O(2)Ca2Cu3 trigonal bipyramids, corners with four equivalent O(1)Sr2Cu3 trigonal bipyramids, edges with four equivalent O(4)Sr4CaCu octahedra, edges with four equivalent O(3)SrCa4Cu octahedra, and faces with two equivalent O(1)Sr2Cu3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 10°.