Rhodium Oxide is a compound made of Rhodium, a metal, and Oxygen, a non-metal. It is a dark grey powdery substance. It can be produced in several ways; Rhodium metal powder be fused with potassium hydrogen sulfate. Adding sodium hydroxide, and then heating converts it into Rhodium Oxide. Its major application is in catalysts, for conversion of gases. Rhodium Oxide transforms into an orthorhombic structure when heated above 750 C. There is no clear discoverer of this compound, but Rhodium itself was discovered by William Hyde Wollaston.