Holmium Oxides: A New Class of Catalysts for Organic Synthesis

Holmium oxide is one of the elements of the erbium oxide mineral with three chemical constituents, known to be an element. The different states of the holmium oxide autochromatic system, the trivalent and coexisting properties of its elements, need to be separated separately. Holmium oxide can form special glasses. The ability to collect spectra of holmium oxide-containing glasses and solutions has identification value. Therefore, the use of spectrometers on sharp peaks has traditionally used standards.

Basic properties of holmium oxide

Holmium oxide chemical formula: Ho2O3

Holmium oxide particle size: micron/submicron/nanoscale

Holmium oxide color: yellow

Crystal form: cubic

Melting point of holmium oxide: 2367 ℃

Density: 8.36 g/cm3

Specific surface area: 2.14 m2/g

Particle size: Nano scale (20nm 50nm 100nm 200nm 500nm)

Micron scale (1um 5um)

Purity: 99.9% 99.99% 99.999%

Appearance properties of holmium metal

Depending on the lighting conditions, holmium oxide exhibits a fairly pronounced color change. It is light yellow under sunlight, and strong orange-red under three primary color light sources, which is almost indistinguishable from erbium oxide under the same illumination, which is related to its sharp phosphorescence emission band. Holmium oxide has a bandgap as wide as 5.3 eV, so it should be colorless. The yellow color of holmium oxide is caused by a large number of lattice defects (such as oxygen vacancies) and internal conversion of Ho³⁺.

The synthetic of holmium oxide

1. Burning method: The holmium nitrate solution is reacted with alkali to generate holmium hydroxide, and then separated and burned to obtain holmium oxide.

2. Using holmium-containing rare earth enrichment as raw material, use solvent extraction method or ion exchange method to separate Ho3+. Then a suitable precipitant is added to obtain the corresponding precipitate, and finally metal holmium is obtained by burning hydroxide, nitrate, oxalate or carbonate.

Applications of holmium oxide

It is used in the manufacture of new light source dysprosium holmium lamps, and can also be used as an additive for yttrium iron to obtain yttrium aluminum garnet and for the preparation of metal holmium.

Holmium oxide can be used as a yellow and red colorant for Soviet diamonds and glass. Glass containing holmium oxide and holmium oxide solution (usually perchloric acid solution) have sharp absorption peaks in the range of 200-900 nm, so they can be used as standards for spectrometer calibration and have been commercialized. Like other rare earth elements, holmium oxide is used as a specialty catalyst, phosphor, and laser material. The holmium laser has a wavelength of about 2.08 μm and can be either pulsed or continuous light. The laser is harmless to the eyes and can be used in medicine, lidar, wind speed measurement and atmospheric monitoring.