Thulium oxide

Thulium oxide (CAS 12036-44-1), also known by its mineralogical designation thulia, is the stable trivalent oxide of thulium (Tm₂O₃) and one of the heavier rare earth oxides within the lanthanide series.

Where is Thulium oxide used?

• Electronics and solar PV: precursor for thulium-doped laser gain media
• Phosphors: thulium emission lines for display and detection luminescence
• Portable X-ray sources: neutron-irradiated Tm₂O₃ targets yield thulium-170 gamma and X-ray emitters for industrial radiography and non-destructive testing
• Surface modification and wetting: Tm₂O₃ as functional additive and coating component in electronics processing and industrial cleaning formulations
• Tm³⁺-activated solid-state lasers operating in the 2 µm spectral region are of interest for photonic and sensing applications.

Good to know: No compendial monograph under USP or Ph. Eur. currently governs thulium oxide; quality assessment relies on supplier-issued certificates of analysis referencing ICP-MS or ICP-OES trace element data. Carries GHS signal word Warning; handle per occupational exposure guidelines and site-specific risk assessments.

Commercial specifications

• Purity 99.9–99.99 % on a Tm₂O₃/TREO basis; TREO ≥ 99 %
• Particle size distribution 1–5 µm for standard powder grades
• Surface area and loss on ignition (LOI) reported on product data sheets as acceptance criteria
• Packaging: 1–5 kg sealed, labelled containers for R&D; 25 kg fibre drums for process scale