Ca4IrO6 crystallizes in the trigonal R-3c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to eight equivalent O(1) atoms. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. Ir(1) is bonded in an octahedral geometry to six equivalent O(1) atoms. O(1) is bonded to one Ca(2), four equivalent Ca(1), and one Ir(1) atom to form a mixture of distorted face, corner, and edge-sharing OCa5Ir octahedra. The corner-sharing octahedral tilt angles range from 0-66°.
Ca4IrO6 crystallizes in the trigonal R-3c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to eight equivalent O(1) atoms. There are a spread of Ca(1)-O(1) bond distances ranging from 2.41-2.78 Å. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. All Ca(2)-O(1) bond lengths are 2.35 Å. Ir(1) is bonded in an octahedral geometry to six equivalent O(1) atoms. All Ir(1)-O(1) bond lengths are 2.05 Å. O(1) is bonded to one Ca(2), four equivalent Ca(1), and one Ir(1) atom to form a mixture of distorted face, corner, and edge-sharing OCa5Ir octahedra. The corner-sharing octahedral tilt angles range from 0-66°.