Rare Earths



Holmium (Ho, atomic number 67).The special absorption bands of holmium were noticed in 1878 by the Swiss chemists Delafontaine and Soret, who announce the existence of an “Element X”. Cleve, of Sweden, later independently discovered the element while working on erbia earth. The element is name is therefore name after Cleve’s native city. Holmia, the yellow oxide, was prepared by Homberg in 1911. Holmium occurs in gadolinite, monazite and in other rare earth minerals. It has been isolated by the reduction of its anhydrous chloride or fluoride with calcium metal. Pure holmium has a metallic to bright silver luster. It is relatively soft and malleable, it is able to stay dry in room temperature, but it rapidly oxidizes in moist air and at elevated temperatures. Holmium metal has unusual magnetic properties. It has the highest magnetic moment of any known element in the periodic table. It has the greatest number of impaired electrons and impaired electrons are what give rise to magnetism. Therefore, Holmium has many uses in magnetic materials. Very few other uses have been found for the element. Like some other rare earths Holmium seems to have a low acute toxic rating.

Some known uses for Holmium are as follows:

  • Magnets
  • Ceramics
  • Lasers