Samarium: Element Properties And Uses

Samarium is known as a rare earth element with peculiar magnetic, optical, and nuclear properties. This metallic element has a silvery brightness with moderate hardness. Samarium is an essential element used in the preparation of high-temperature permanent magnets, the core parts of some reactors, lasers, and specialised applications in the medical field.

Chemical Properties of Samarium

Samarium is also a member of the lanthanide series and shares usual chemical properties of rare earth elements, but it demonstrates some distinctive characteristics as well. It is mostly found in its +3 oxidation state, which forms stable compounds with oxygen, halogens, sulphur, and other non-metals. Samarium oxides and halides are quite commonly used as precursors in various industries.

At room conditions, samarium reacts slowly with air to produce a thin, strongly adhering oxide layer on its surface. This oxide layer serves as a protective coating against further oxidation; this is referred to as self-passivated elements.

Samarium has greater reactivity when compared to other heavier lanthanides, but due to this natural passivation, it has relatively better handling stability.

When samarium reacts with water, it produces hydrogen gas along with hydroxide compounds, especially under high temperature conditions.

Physical Properties of Samarium

Samarium is moderately dense and has a hexagonal crystal structure. This physical property of the element itself is the direct reason for its application at high temperatures and high stresses.

The high melting point and stability of samarium's crystal structure make this element particularly valuable in alloy production and magnet constructions. For more information, please check Stanford Advanced Materials (SAM).

Magnetic and Optical Properties

Magnetic Properties

Samarium has a very complex magnetic pattern owing to the electron structure. Although pure samarium has been found to have antiferromagnetic properties at low temperatures, the main magnetic component comes from samarium-cobalt alloys (SmCo).

SmCo magnets are widely valued for their excellent demagnetisation resistance, high coercive force, and good performance ability at temperatures above 300°C. Due to these characteristics, they play a paramount role in aerospace, precision motors, and military technology.

Optical Properties

These optical properties make it possible to apply samarium-doped materials in laser technology, optical filters, and luminescent devices.

History and Development of Samarium

The element samarium was discovered by a French chemist named Paul-Émile Lecoq de Boisbaudran in 1879 by analysing spectral lines from the mineral samarskite. The element is named for the mineral, named in turn for a Russian mining official named Vasili Samarsky-Bykhovets, making it the first element named for another person.

Initially, when samarium was first discovered, it remained of great importance to scientists because it was difficult to separate rare earth elements from each other. However, with technological advancements in the 20th century, ion exchange chromatography and solvent extraction processes became possible, making it feasible to produce samarium on a larger scale with high purity.

However, the true importance of samarium in technology emerged in the 1960s and 1970s when samarium-cobalt permanent magnets were invented. These magnets were much better than previous magnets because of their higher heat resistance and coercive forces. After this point, research began to introduce samarium to new applications in the field of nuclear engineering, cancer treatments, and specialty optics.

Applications of Samarium

One of the main applications of samarium is in the preparation of samarium-cobalt permanent magnets. The use of these magnets extends to various applications, especially in the electric motor industry, aerospace, sensors, and the military.

In nuclear applications, samarium—specifically samarium-149—is used as a neutron absorber in nuclear reactors. This is because a high neutron capture cross-section makes its application in the nuclear reactor favourable. Additionally, samarium compounds are used in control rods/burnable poisons in nuclear reactors.

Samarium is used in lasers, infrared optics, and phosphors. In medical applications, some radioisotopes, like samarium-153, are used in targeted therapy for treating cancer patients, specifically for pain relief from metastatic bone pain. The above applications have demonstrated the versatility of samarium in different applications in industrious as well as medical settings.

Processing and Making Processes

Samarium is extracted from the rare earth minerals monazite and bastnasite. After being mined, the ore can be mechanically beneficiated to enhance the concentration of the rare earth elements. Various chemical methods, solvent extraction, and ion exchange can be employed to separate samarium from the other elements in the lanthanides.

After a samarium compound is obtained, it is reduced by means of calcium or other reactive metals to obtain samarium. Today, samarium production is designed to be efficient and pure, following several decades of evolution in techniques used for processing rare earth metals.

Frequently Asked Questions

How is samarium obtained from natural elements?

It can be extracted from minerals like monazite and bastnasite through mechanical separations followed by solvent extraction and ion exchange.

What are the prominent uses of samarium?

Samarium also finds applications in the preparation of samarium-cobalt magnets, nuclear reactor parts, lasers, optical materials, and in certain medical applications.

Is samarium used in medicine?

Yes. Radioactive substances, such as samarium-153, have applications in the field of cancer treatments and imaging.

What is the significance of samarium in contemporary technology?

Heat resistance, magnetic properties, and known chemical reactions make this material a highly wanted component in some applications.