Ca2IrRhO6 crystallizes in the monoclinic C2/m space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), three equivalent O(2), and three equivalent O(3) atoms. Ir(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form IrO6 octahedra that share corners with two equivalent Rh(1)O6 octahedra and edges with two equivalent Ir(1)O6 octahedra. The corner-sharing octahedral tilt angles are 45°. Rh(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form RhO6 octahedra that share corners with two equivalent Ir(1)O6 octahedra and edges with two equivalent Rh(1)O6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1), one Ir(1), and one Rh(1) atom to form distorted OCa2IrRh tetrahedra that share corners with four equivalent O(3)Ca3Ir2 square pyramids, corners with four equivalent O(2)Ca3Rh2 square pyramids, corners with four equivalent O(1)Ca2IrRh tetrahedra, edges with three equivalent O(3)Ca3Ir2 square pyramids, and edges with three equivalent O(2)Ca3Rh2 square pyramids. In the second O site, O(2) is bonded to three equivalent Ca(1) and two equivalent Rh(1) atoms to form distorted OCa3Rh2 square pyramids that share corners with two equivalent O(2)Ca3Rh2 square pyramids, corners with seven equivalent O(3)Ca3Ir2 square pyramids, corners with four equivalent O(1)Ca2IrRh tetrahedra,  an edgeedge with one O(3)Ca3Ir2 square pyramid, edges with five equivalent O(2)Ca3Rh2 square pyramids, and edges with three equivalent O(1)Ca2IrRh tetrahedra. In the third O site, O(3) is bonded to three equivalent Ca(1) and two equivalent Ir(1) atoms to form distorted OCa3Ir2 square pyramids that share corners with two equivalent O(3)Ca3Ir2 square pyramids, corners with seven equivalent O(2)Ca3Rh2 square pyramids, corners with four equivalent O(1)Ca2IrRh tetrahedra,  an edgeedge with one O(2)Ca3Rh2 square pyramid, edges with five equivalent O(3)Ca3Ir2 square pyramids, and edges with three equivalent O(1)Ca2IrRh tetrahedra.
Ca2IrRhO6 crystallizes in the monoclinic C2/m space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), three equivalent O(2), and three equivalent O(3) atoms. Both Ca(1)-O(1) bond lengths are 2.32 Å. There are two shorter (2.43 Å) and one longer (2.47 Å) Ca(1)-O(2) bond length. There are two shorter (2.49 Å) and one longer (2.57 Å) Ca(1)-O(3) bond length. Ir(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form IrO6 octahedra that share corners with two equivalent Rh(1)O6 octahedra and edges with two equivalent Ir(1)O6 octahedra. The corner-sharing octahedral tilt angles are 45°. Both Ir(1)-O(1) bond lengths are 1.96 Å. All Ir(1)-O(3) bond lengths are 2.04 Å. Rh(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form RhO6 octahedra that share corners with two equivalent Ir(1)O6 octahedra and edges with two equivalent Rh(1)O6 octahedra. The corner-sharing octahedral tilt angles are 45°. Both Rh(1)-O(1) bond lengths are 2.00 Å. All Rh(1)-O(2) bond lengths are 2.04 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1), one Ir(1), and one Rh(1) atom to form distorted OCa2IrRh tetrahedra that share corners with four equivalent O(3)Ca3Ir2 square pyramids, corners with four equivalent O(2)Ca3Rh2 square pyramids, corners with four equivalent O(1)Ca2IrRh tetrahedra, edges with three equivalent O(3)Ca3Ir2 square pyramids, and edges with three equivalent O(2)Ca3Rh2 square pyramids. In the second O site, O(2) is bonded to three equivalent Ca(1) and two equivalent Rh(1) atoms to form distorted OCa3Rh2 square pyramids that share corners with two equivalent O(2)Ca3Rh2 square pyramids, corners with seven equivalent O(3)Ca3Ir2 square pyramids, corners with four equivalent O(1)Ca2IrRh tetrahedra,  an edgeedge with one O(3)Ca3Ir2 square pyramid, edges with five equivalent O(2)Ca3Rh2 square pyramids, and edges with three equivalent O(1)Ca2IrRh tetrahedra. In the third O site, O(3) is bonded to three equivalent Ca(1) and two equivalent Ir(1) atoms to form distorted OCa3Ir2 square pyramids that share corners with two equivalent O(3)Ca3Ir2 square pyramids, corners with seven equivalent O(2)Ca3Rh2 square pyramids, corners with four equivalent O(1)Ca2IrRh tetrahedra,  an edgeedge with one O(2)Ca3Rh2 square pyramid, edges with five equivalent O(3)Ca3Ir2 square pyramids, and edges with three equivalent O(1)Ca2IrRh tetrahedra.