Iridium(III) sulfide is the inorganic compound with the formula Ir₂S₃. It is an insoluble black solid, prepared by heating a mixture of elemental iridium and sulfur^{[citation needed]}. Crystals can be grown by chemical vapor transport using bromine as the transporting agent. The structure consists of octahedral and tetrahedral Ir and S centers, respectively. No close Ir-Ir contacts are observed. Rh₂S₃ and Rh₂Se₃ adopt the same structure.