thulium oxide (Tm2O3) is a thermally stable, pale green solid compound. It is a good thulium source that finds use in glass, optic and ceramic applications. It is also used as a nuclear reactor control material and as a X-ray transmission device.
The element thulium (pronounced /’thju:li@m/) is the second-least abundant of the lanthanide metals, after radioactively unstable promethium. It has a bright silvery-gray luster and is soft and easily workable.
Several naturally occurring isotopes of thulium exist, most of which have very short half-lives. The most stable isotope is thulium-169, which is produced by bombarding the element with atomic nuclei in a nuclear reactor.
In nature, thulium is mainly dissolved in dilute sulfuric acid and reacts with HCl to form hydrogen gas and thulium chloride. It is a strong paramagnet above 56 K and a weaker antiferromagnetic below that temperature.
It has a wide range of industrial and research applications, most notably as a dopant for YAG lasers and in some high-temperature superconducting oxides. It is also employed in arc lighting, and as the radiation source for portable x-ray equipment.
The trivalent thulium ions, Tm3+, emit a blue luminescence when excited. It can be oxidized in air to form thulium oxide, or reduced with lanthanum metal to produce the crystalline substance erbia (erbium oxide). It can also be isolated by ion exchange from monazite or by solvent-solvent extraction.