Sr7Ca(IrO6)2 crystallizes in the trigonal R32 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. In the third Sr site, Sr(3) is bonded in a 6-coordinate geometry to six equivalent O(2) atoms. Ca(1) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. Ir(1) is bonded in an octahedral geometry to three equivalent O(1) and three equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(2) is bonded to one Sr(3), two equivalent Sr(1), two equivalent Sr(2), and one Ir(1) atom to form distorted OSr5Ir octahedra that share corners with seven equivalent O(1)Sr4CaIr octahedra, corners with eight equivalent O(2)Sr5Ir octahedra,  an edgeedge with one O(2)Sr5Ir octahedra, edges with three equivalent O(1)Sr4CaIr octahedra, faces with two equivalent O(1)Sr4CaIr octahedra, and faces with three equivalent O(2)Sr5Ir octahedra. The corner-sharing octahedral tilt angles range from 1-64°. In the second O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sr(2), one Ca(1), and one Ir(1) atom to form distorted OSr4CaIr octahedra that share corners with seven equivalent O(2)Sr5Ir octahedra, corners with eight equivalent O(1)Sr4CaIr octahedra,  an edgeedge with one O(1)Sr4CaIr octahedra, edges with three equivalent O(2)Sr5Ir octahedra, faces with two equivalent O(2)Sr5Ir octahedra, and faces with three equivalent O(1)Sr4CaIr octahedra. The corner-sharing octahedral tilt angles range from 1-64°.
Sr7Ca(IrO6)2 crystallizes in the trigonal R32 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. There are two shorter (2.56 Å) and two longer (2.69 Å) Sr(1)-O(1) bond lengths. There are two shorter (2.64 Å) and two longer (2.83 Å) Sr(1)-O(2) bond lengths. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. There are two shorter (2.66 Å) and two longer (2.81 Å) Sr(2)-O(1) bond lengths. There are two shorter (2.58 Å) and two longer (2.63 Å) Sr(2)-O(2) bond lengths. In the third Sr site, Sr(3) is bonded in a 6-coordinate geometry to six equivalent O(2) atoms. All Sr(3)-O(2) bond lengths are 2.46 Å. Ca(1) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. All Ca(1)-O(1) bond lengths are 2.37 Å. Ir(1) is bonded in an octahedral geometry to three equivalent O(1) and three equivalent O(2) atoms. All Ir(1)-O(1) bond lengths are 2.07 Å. All Ir(1)-O(2) bond lengths are 2.08 Å. There are two inequivalent O sites. In the first O site, O(2) is bonded to one Sr(3), two equivalent Sr(1), two equivalent Sr(2), and one Ir(1) atom to form distorted OSr5Ir octahedra that share corners with seven equivalent O(1)Sr4CaIr octahedra, corners with eight equivalent O(2)Sr5Ir octahedra,  an edgeedge with one O(2)Sr5Ir octahedra, edges with three equivalent O(1)Sr4CaIr octahedra, faces with two equivalent O(1)Sr4CaIr octahedra, and faces with three equivalent O(2)Sr5Ir octahedra. The corner-sharing octahedral tilt angles range from 1-64°. In the second O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sr(2), one Ca(1), and one Ir(1) atom to form distorted OSr4CaIr octahedra that share corners with seven equivalent O(2)Sr5Ir octahedra, corners with eight equivalent O(1)Sr4CaIr octahedra,  an edgeedge with one O(1)Sr4CaIr octahedra, edges with three equivalent O(2)Sr5Ir octahedra, faces with two equivalent O(2)Sr5Ir octahedra, and faces with three equivalent O(1)Sr4CaIr octahedra. The corner-sharing octahedral tilt angles range from 1-64°.