Holmium
Element Name: Holmium
Atomic Number: 67
Atomic Mass: 164.93032
Atomic Symbol: Ho
Melting Point: 1474° C
Boiling Point: 2700° C
Two people discovered holmium independently. In 1878 Marc Delafontaine and Jacques-Louis Soret noted strange absorption bands from something they called element “X”, but in 1879 Per Teodor Cleve managed to purify holmium oxide from a sample of erbium oxide. The name “Holmium” comes from the Greek word for Stockholm, Holmia. It’s a bright silver-white rare earth that is soft, ductile, and malleable. Holmium is trivalent in nearly all laboratory chemistry. Like other rare earths, Holmium has an emission spectrum that depends on the light shone on it. It has a low toxicity. It has 30 known isotopes, but only one of them, Holmium-165, is stable and occurs in nature.
Interesting Facts:
Holmium has the largest magnetic moment of any element (10.6µB) and has other interesting magnetic properties. It is normally paramagnetic, but is ferromagnetic at extremely low temperatures (19K or lower). The solid-state lasers created by holmium doped Yttrium-aluminum-garnet is used in laser surgery. Optical spectrophotometers use holmium oxide mixed with perchloric acid and merged into quartz as a calibration standard. This is because that particular mix has sharp absorption peaks between 200 and 900 nm (which is a useful range for human vision). A radioactive isotope of Holmium (Ho-166m1) is used to calibrate gamma ray spectrometers.
Sources:
Holmium is not found in its elemental form in nature. It is stable in dry air at room temperatures, but it becomes an oxide when exposed to moisture or heated. You can find Holmium in a number of rare earth minerals, chiefly gadolinite and monazite. Holmium is a rare, even for a lanthanide, and is only found a 1.3 parts per million on the earth’s surface (and around 500 parts per trillion in the universe).
Industrial Uses:
The most prominent use of Holmium is derived from its magnetic strength. It can be used to create large artificially generated magnetic fields if it is used a magnetic pole piece. A familiar example of a large magnetic field being used is in an MRI machine. Holmium is a good neutron absorber and can be used in nuclear controls rods as burnable poison. Holmium is used in small quantities in yttrium-iron-garnet (YIG) and yttrium-lanthanum-fluoride (YLF) lasers. In more mundane cases, holmium oxide can be used as a yellow or red pigment for glass and cubic zirconia.
References:
“Facts About Holmium.” Livescience. Livescience.com, 22 July 2013. Web. 26 July
2016.
“Holmium.” Wikipedia. Wikimedia Foundation, n.d. Web. 26 July 2016.
“Holmium Element Facts / Chemistry.” Chemicool. Chemicool.com, 17 Oct. 2012.
Web. 26 July 2016.
Gray, Theodore W., and Nick Mann. The Elements: A Visual Exploration of Every
Known Atom in the Universe. New York: Black Dog & Leventhal, 2009. Print.