CaIrO3 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 7-coordinate geometry to one O(1) and six equivalent O(2) atoms. Ir(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form a mixture of distorted edge and corner-sharing IrO6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1) and four equivalent Ir(1) atoms to form OCaIr4 square pyramids that share corners with four equivalent O(1)CaIr4 square pyramids, corners with six equivalent O(2)Ca3Ir tetrahedra, edges with four equivalent O(1)CaIr4 square pyramids, and edges with four equivalent O(2)Ca3Ir tetrahedra. In the second O site, O(2) is bonded to three equivalent Ca(1) and one Ir(1) atom to form distorted OCa3Ir tetrahedra that share corners with three equivalent O(1)CaIr4 square pyramids, corners with ten equivalent O(2)Ca3Ir tetrahedra, edges with two equivalent O(1)CaIr4 square pyramids, and edges with three equivalent O(2)Ca3Ir tetrahedra.
CaIrO3 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 7-coordinate geometry to one O(1) and six equivalent O(2) atoms. The Ca(1)-O(1) bond length is 2.43 Å. There are two shorter (2.35 Å) and four longer (2.37 Å) Ca(1)-O(2) bond lengths. Ir(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form a mixture of distorted edge and corner-sharing IrO6 octahedra. The corner-sharing octahedral tilt angles are 3°. Both Ir(1)-O(2) bond lengths are 1.90 Å. All Ir(1)-O(1) bond lengths are 2.31 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1) and four equivalent Ir(1) atoms to form OCaIr4 square pyramids that share corners with four equivalent O(1)CaIr4 square pyramids, corners with six equivalent O(2)Ca3Ir tetrahedra, edges with four equivalent O(1)CaIr4 square pyramids, and edges with four equivalent O(2)Ca3Ir tetrahedra. In the second O site, O(2) is bonded to three equivalent Ca(1) and one Ir(1) atom to form distorted OCa3Ir tetrahedra that share corners with three equivalent O(1)CaIr4 square pyramids, corners with ten equivalent O(2)Ca3Ir tetrahedra, edges with two equivalent O(1)CaIr4 square pyramids, and edges with three equivalent O(2)Ca3Ir tetrahedra.