Tungsten(III) oxide (W<sub>2</sub>O<sub>3</sub>) is a compound of tungsten and oxygen. It has been reported (2006) as being grown as a thin film by atomic layer deposition at temperatures between 140 and 240 ðC using W<sub>2</sub>(N(CH<sub>3</sub>)<sub>2</sub>)<sub>6</sub> as a precursor. It is not referred to in major textbooks. Some older literature refers to the compound W<sub>2</sub>O<sub>3</sub> but as the atomic weight of tungsten was believed at the time to be 92 (i.e., approximately half the modern accepted value of 183.84) the compound actually being referred to was WO<sub>3</sub>.
Reports about the compound date back to at least the 1970s, but only in as thin films or surfaces â no bulk synthesis of the material is known.
Tungsten(III) oxide is used in various types of infrared absorbing coatings and foils.