Iridium disulfide is the binary inorganic compound with the formula IrS<sub>2</sub>. Prepared by the direct reaction of the elements, the compound adopts the pyrite crystal structure at high pressure. At normal atmospheric pressures, an orthorhombic polymorph is observed.. The high- and low-pressure forms both feature octahedral Ir centers, but the SâÂÂS distances are pressure dependent. Although not practical, IrS<sub>2</sub> is a highly active catalyst for hydrodesulfurization.