Samarium (Sm)


  • Symbol: Sm
  • Atomic Number: 62
  • Atomic Weight: 150.36
  • Element Classification: Lanthanide
  • Discovered By: Paul Émile Lecoq de Boisbaudran
  • Discovery Date: 1879
  • Name Origin: Named after the mineral samarskite, which was named in honor of Colonel Vasili Samarsky-Bykhovets
  • Density(g/cc): 7.52
  • Melting Point: 1072°C
  • Boiling Point: 1900°C
  • Appearance: Silvery-white, hard, and brittle metal
  • Atomic Radius(pm): 180


Samarium was discovered by French chemist Paul Émile Lecoq de Boisbaudran in 1879. He isolated samarium oxide from the mineral samarskite, which is a complex rare earth mineral. The element was named after the mineral, which in turn was named in honor of Colonel Vasili Samarsky-Bykhovets, a Russian mine official who provided the mineral samples. The discovery of samarium contributed to the understanding of rare earth elements and their separation and identification.

Relation to Other Elements

Samarium is part of the lanthanide series, a group of elements that share similar chemical properties, such as forming trivalent ions (+3) and having high magnetic susceptibility. Samarium is distinguished by its significant role in various technological applications, particularly due to its magnetic properties. It is less abundant than some of the more common lanthanides, like cerium and neodymium, but it is more abundant than others, like europium and gadolinium.

Natural Occurrence

Samarium is not found free in nature but is contained within various minerals, including monazite and bastnasite, which are important sources of rare earth elements. The extraction and purification of samarium from these minerals require complex metallurgical processes, as it typically occurs together with other lanthanides.


Samarium has a variety of specialized uses:

  • Magnets: Samarium-cobalt (SmCo) magnets are known for their high magnetic strength and exceptional thermal stability, making them ideal for use in aerospace, military, and industrial applications where performance at high temperatures is required.
  • Nuclear Reactors: Samarium is used as a neutron absorber in nuclear reactors due to its ability to capture neutrons and its good thermal neutron absorption cross-section.
  • Cancer Treatment: Samarium-153 lexidronam (Quadramet) is a radioactive isotope of samarium used in medicine to treat the pain associated with bone cancer, as it targets and accumulates in cancerous tissues.
  • Catalysts: Samarium oxide (Sm₂O₃) is used as a catalyst in certain organic chemical reactions, including the dehydration and dehydrogenation of ethanol.

The discovery of samarium and the development of its applications, especially in the production of high-strength magnets and its use in nuclear and medical fields, underline the importance of rare earth elements in advanced technologies and healthcare.

Promethium (Pm)

Europium (Eu)