3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||253.8092 g/mol|
|Appearance||dark grey odorless powder|
|Melting point||1,100 °C (2,010 °F; 1,370 K) (decomposes)|
|Solubility||insoluble in aqua regia|
a = 512.7 pm (hexagonal setting), c = 1385.3 pm (hexagonal setting)
|H302+H332, H315, H319, H335|
|P280, P301+P330+P331, P302+P352, P304+P340, P312, P332+P313, P337+P313|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Rhodium(III) oxide (or Rhodium sesquioxide) is the inorganic compound with the formula Rh2O3. It is a gray solid that is insoluble in ordinary solvents.
Rh2O3 has been found in two major forms. The hexagonal form adopts the corundum structure. It transforms into an orthorhombic structure when heated above 750 °C.
Rhodium oxide can be produced via several routes:
Rhodium oxide films behave as a fast two-color electrochromic system: Reversible yellow ↔ dark green or yellow ↔ brown-purple color changes are obtained in KOH solutions by applying voltage ~1 V.
Rhodium oxide films are transparent and conductive, like indium tin oxide (ITO) - the common transparent electrode, but Rh2O3 has 0.2 eV lower work function than ITO. Consequently, deposition of rhodium oxide on ITO improves the carrier injection from ITO thereby improving the electrical properties of organic light-emitting diodes.
Rhodium oxides are catalysts for hydroformylation of alkenes, N2O production from NO, and the hydrogenation of CO.