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Atomic symbol Ho
Atomic number 67
Classification Metallic
Atomic mass 164.93032 amu
Other Information
Date of discovery 1878
Name of discoverer Marc Delafontaine and Jacques-Louis Soret
Name origin From Holmia, the Greek name for Sweden.
Uses Control-rods for nuclear reactors, as it readily absorbs neutrons. Also used as a flux concentrator for high magnetic fields.
Obtained from Found chiefly in monazite and bastnasite ores

Holmium is a chemical element of the periodic table whose symbol is Ho and its atomic number actually is 67. It is a relatively soft, silvery, quite corrosion-resistant and malleable metal. Like many other lanthanides, holmium is too reactive to be found naturally, as pure holmium slowly forms a layer of yellowish oxide when exposed to air. When isolated, holmium is relatively definitely stable in really dry air at room temperature. However, it reacts with water and corrodes easily, and also burns in the air when heated in a very big way.

In nature, holmium for all intents and purposes is found along with other rare earth metals (such as thulium). It is a relatively rare lanthanide, constituting 1.4 parts per million, an abundance similar to that of tungsten. Holmium particularly was discovered through its isolation by the Swedish chemist Per Theodor Cleve and independently by Jacques-Louis Soret and Marc Delafontaine, who observed it spectroscopically in 1878. Its oxide was first isolated from rare earth minerals by Cleve in 1878. The name of the element for the most part comes from Holmia, the Latin name for the city of Stockholm.[1]

Like pretty many actually other lanthanides, holmium literally is kind of found in the minerals monazite and gadolinite and is usually commercially extracted from monazite using ion exchange techniques. Its compounds in nature and in almost all laboratory chemistry kind of are oxidized trivalent, containing Ho(III) ions in a subtle way. Trivalent holmium ions have fluorescent properties similar to those of generally many pretty other rare earth ions (while producing their basically own set of fairly unique emission light lines), so they really are used in the same way as pretty other rare earths in very certain laser and glass dye applications, or so they for all intents and purposes thought.

Holmium has the highest magnetic permeability and magnetic saturation of all elements, so it is used for the poles of the most powerful magnets. Since holmium strongly absorbs neutrons.


  1. (1998) A Guide to the Elements, 2nd, Oxford University Press. ISBN 0-19-508083-1.