Acetates Borates

Like all other rare earths, holmium is not naturally found as a free element. It does occur combined with other elements in gadolinite, monazite and other rare-earth minerals. Holmium is a relatively soft and malleable element that is fairly corrosion-resistant and stable in dry air at standard temperature and pressure. In moist air and at higher temperatures, however, it quickly oxidizes, forming a yellowish oxide. In pure form, holmium possesses a metallic, bright silvery luster.

For later lanthanides, anhydrous acetates are synthesized by crystallization from diluted acetic acid solutions of their oxides and caesium acetate at 120°C. Holmium acetate adopts a structure shared with other lanthanide acetate (Ln(CH3COO)3 where Ln= Sm-Er, Y). Here, Holomium occupies two slightly different eight coordinate sites, with average Ho—O distances of 2.370 Å and 2.371 Å.

The hydrated and anhydrous lanthanide acetates have several coordination spheres and may have coordination numbers of 6–10. The acetate ions may be either monodentate, bidentate or polymerizing ligands. As the ionic radius reduces in a sequence of lanthanide ions, the coordination environment of both lanthanide ions and the acetate ligands can be studied as the size of the coordination sphere reduces.

Rare earth acetates represent an important class of the compounds having a variety of technical, industrial and biological applications. Rare earth acetates and acetyl acetonate are good candidates for the preparation of rare earth oxide nanoparticles. Rare earth oxide nanoparticles such as ZrO2 , Gd2 O3 with controllable sizes and shapes synthesized by radiation induced thermal decomposition of rare earth acetate and acetyl acetonates.

Holmium has the highest magnetic strength of any element, and therefore is used to create the strongest artificially generated magnetic fields, Holmium is used in yttrium-iron-garnet (YIG) and yttrium-lanthanum-fluoride (YLF) solid-state lasers found in microwave equipment (which are in turn found in a variety of medical and dental settings).