Iridium(III) sulfide is the inorganic compound with the formula Ir<sub>2</sub>S<sub>3</sub>. It is an insoluble black solid, prepared by heating a mixture of elemental iridium and sulfur. 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. Rh<sub>2</sub>S<sub>3</sub> and Rh<sub>2</sub>Se<sub>3</sub> adopt the same structure.