Terbium oxide

Terbium oxide (CAS 12037-01-3), formally terbium(III,IV) oxide with the composition Tb₄O₇, is a mixed-valence rare earth oxide and one of the most technically important compounds in the terbium series.

Where is Terbium oxide used?

• Electronics and displays: primary precursor for green-emitting terbium-activated lanthanum phosphate and related rare earth phosphor systems
• The Tb³⁺ ion provides efficient green luminescence under UV and electron-beam excitation, making high-purity Tb₄O₇ a critical input for fluorescent lamps, cathode-ray phosphors, and solid-state lighting formulations
• Permanent magnets and magnetostrictive applications: feedstock for metallic terbium additions to NdFeB magnet alloys, where small terbium concentrations at grain boundaries increase coercivity and high-temperature performance
• Starting material for Terfenol-D (terbium–dysprosium–iron), the principal commercial magnetostrictive alloy used in actuators, sonar transducers, and precision positioning devices
• Magneto-optical glass formulations: dopant; glasses with elevated Tb³⁺ content exhibit a high Verdet constant, enabling Faraday rotators and optical isolators used in laser systems and fibre-optic infrastructure
• Catalytic promoter in certain oxidation catalyst formulations, where its mixed Tb³⁺/Tb⁴⁺ redox couple contributes oxygen storage and release capacity analogous to that observed with cerium oxide

Good to know: A dark brown to black powder with a specific gravity of approximately 7.3 g/cm³ and a melting point in the region of 2,410 °C. Loss on ignition (LOI) and residual moisture are the standard incoming quality checks applied by ceramic and phosphor manufacturers.

Commercial specifications

• 99.9 % to 99.99 % Tb₄O₇ on a total rare earth oxide basis (Tb₄O₇/TREO ≥ 99.9 %, TREO ≥ 99 %)
• Particle size distributions customisable from sub-micron to coarser powders
• Packaging: 100 g to 5 kg in sealed polyethylene-lined containers; multi-kilogram lots in moisture-resistant packaging