Holmium oxide

Holmium oxide (CAS 12055-62-8), also known as holmia and carrying the alternative CAS 39455-61-3, is a pale yellow rare earth oxide with the formula Ho₂O₃. It belongs to the lanthanide series and combines a distinctive absorption spectrum with optical and thermal stability.

Where is Holmium oxide used?

• Ceramics and specialty glass: colourant for cubic zirconia and related oxide systems, contributing controlled tints stable under high-temperature processing
• Analytical laboratories: wavelength calibration standard for UV-Vis spectrophotometers, with strong absorption bands from roughly 240 nm to 650 nm
• Solid-state lasers: precursor for holmium-doped yttrium aluminium garnet (Ho:YAG) crystals
• Ho:YAG lasers emit in the mid-infrared at approximately 2.1 µm for industrial cutting, ranging and sensing systems.
• Electronics and photovoltaics: surface-modification and wetting-control additive in thin-film and coating formulations

Good to know: The oxide form is the preferred input material for crystal-growth and phosphor manufacturing. Loss on ignition (LOI) is a standard quality parameter reported alongside purity.

Commercial specifications

• 99.9 % purity, quoted as Ho₂O₃/TREO ≥ 99.9 %
• Total rare earth oxide (TREO) content ≥ 99 %
• Fine powder passing a −325 mesh screen (nominally ≤ 44 µm)
• High-purity analytical lots in 1–5 kg containers; bulk technical grade in 25 kg drums or multi-layer bags, larger quantities in 500–1,000 kg big bags