The characterization of calcium iridium oxides

Several calcium iridium oxides were prepared by solid state reactions and by a hydroxide precipitation technique. These phases were characterized by X-ray powder diffraction data, electrical and magnetic properties. The calcium-rich phase, Ca₄IrO₆, was an insulator exhibiting Curie-Weiss behavior above 77°K with a Weiss constant of ?47°K and a magnetic moment of 1.76 μ_B.Ca₂IrO₄ is a semiconductor and the temperature-dependent susceptibility above 77°K was analyzed in terms of one-dimensional linear chains of octahedrally coordinated Ir⁴⁺ ions.Two CaIrO₃ phases were isolated, but only the orthorhombic perovskite modification was sufficiently pure for magnetic studies. It was Pauli paramagnetic with metallic conductivity.