Holmium (Ho), chemical element, a rare-earth metal of the lanthanide series of the periodic table. Holmium is a moderately hard, silvery white metal that is relatively stable in air. It readily reacts with diluted acids but does not react with either diluted or concentrated hydrofluoric acid (HF), due to formation of a protective surface layer of HoF3. Continue reading from Encyclopedia Britannica
Holmium was discovered at Geneva in 1878 by Marc Delafontaine and Louis Soret, and independently by Per Teodor Cleve at Uppsala, Sweden. Both teams were investigating yttrium, which was contaminated with traces of other rare earths (aka lanthanoids) and had already yielded erbium which was later to yield ytterbium. Cleve looked more closely at what remained after the ytterbium had been removed, and realised it must contain yet other elements because he found that its atomic weight depended on its source. He separated holmium from erbium in 1878. Delafontaine and Soret also extracted it from the same source, having seen unexplained lines in the atomic spectrum. We cannot be certain that either group had produced a pure sample of the new element because yet another rare-earth, dysprosium, was to be extracted from holmium. Continue reading from Royal Society of Chemistry
Holmium occurs in gadolinite, monazite, and in other rare earth minerals. The element Holmium is named after the Latin translation of Per Teodor Cleve's home city of Stockholm (Holmia). Like all lanthanides or rare earth metals, holmium has a metallic silver sheen and is fairly soft and malleable. While it is stable in dry air at room temperature it rapidly oxidizes in moist air and at elevated temperatures. Holmium has no known commercial uses. Continue reading from LiveScience
