Holmium

Holmium is a <a href="/facts/Chemical_element/0jducgWD">chemical element</a>; it has <a href="/facts/Symbol_(chemistry)/2Fe1VAL0">symbol</a> Ho and <a href="/facts/Atomic_number/bgAr581S">atomic number</a> 67. It is a <a href="/facts/Rare-earth_element/PQSUQumk">rare-earth element</a> and the eleventh member of the <a href="/facts/Lanthanide_series/rt3XIRCl">lanthanide series</a>. It is a relatively soft, silvery, fairly <a href="/facts/Corrosion/lIC7H4we">corrosion</a>-resistant and <a href="/facts/Malleable/SBJsahEk">malleable</a> metal. Like many other lanthanides, holmium is too reactive to be found in native form, as pure holmium slowly forms a yellowish <a href="/facts/Oxide/DXtoVe1C">oxide</a> coating when exposed to air. When isolated, holmium is relatively stable in dry air at room temperature. However, it reacts with water and corrodes readily, and also burns in air when heated.
In nature, holmium occurs together with the other rare-earth metals (like <a href="/facts/Thulium/G2905xhd">thulium</a>). It is a relatively rare lanthanide, making up 1.4 <a href="/facts/Parts_per_million/PozRuoLM">parts per million</a> of the <a href="/facts/Earth%2527s_crust/VSy2u31r">Earth's crust</a>, an abundance similar to <a href="/facts/Tungsten/WYwbNDYX">tungsten</a>. Holmium was discovered through isolation by Swedish chemist <a href="/facts/Per_Theodor_Cleve/0KGIUxKW">Per Theodor Cleve</a>. It was also independently discovered by <a href="/facts/Jacques-Louis_Soret/uYAGlgaQ">Jacques-Louis Soret</a> and <a href="/facts/Marc_Delafontaine/ffzDsuEV">Marc Delafontaine</a>, who together observed it <a href="/facts/Spectroscopy/mj71FuNK">spectroscopically</a> in 1878. Its oxide was first isolated from rare-earth ores by Cleve in 1878. The element's name comes from Holmia, the Latin name for the city of <a href="/facts/Stockholm/sD74W4Pm">Stockholm</a>.
Like many other <a href="/facts/Lanthanides/rt3XIRCl">lanthanides</a>, holmium is found in the minerals <a href="/facts/Monazite/an71GkIH">monazite</a> and <a href="/facts/Gadolinite/kahQI57c">gadolinite</a> and is usually commercially extracted from monazite using <a href="/facts/Ion-exchange/C2DPoGqg">ion-exchange</a> techniques. Its compounds in nature and in nearly all of its laboratory chemistry are trivalently oxidized, containing Ho(III) <a href="/facts/Ions/fXGhgbFc">ions</a>. Trivalent holmium ions have <a href="/facts/Fluorescent/qsJVT2qP">fluorescent</a> properties similar to many other rare-earth ions (while yielding their own set of unique <a href="/facts/Emission_spectrum/fxumR717">emission light lines</a>), and thus are used in the same way as some other rare earths in certain <a href="/facts/Laser/jk6PTvvT">laser</a> and glass-colorant applications.
Holmium has the highest <a href="/facts/Magnetic_permeability/GA7CcRLU">magnetic permeability</a> and <a href="/facts/Saturation_(magnetic)/QvhGEldn">magnetic saturation</a> of any element and is thus used for the <a href="/facts/Pole_piece/FEj9W1bw">pole pieces</a> of the strongest static <a href="/facts/Magnet/vvrg6VSk">magnets</a>. Because holmium strongly absorbs <a href="/facts/Neutrons/oRCM1geb">neutrons</a>, it is also used as a <a href="/facts/Burnable_poison/bkruR3yz">burnable poison</a> in <a href="/facts/Nuclear_reactors/8xqjIbge">nuclear reactors</a>.

Holmium open-in-new

Holmium