Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

Samarium Element in Chemistry

Reviewed by:
ffImage
hightlight icon
highlight icon
highlight icon
share icon
copy icon

What is Samarium Definition Properties Electronic Configuration and Uses

What is Samarium?

(Image to be added soon)

To explain what Samarium is, it is a chemical element which is represented by the symbol of the Sm element in the periodic table and the atomic number of Samarium is 62. In the year 1879, Samarium was discovered by Paul Emile Lecoq de Boisbaudran. It is a silvery, hard type of metal which oxidizes slowly in the air. It is a member of the lanthanide series which makes Samarium assuming oxidation state +3. Monoxide SmO, monochalcogenides Sms, SmSe and SmTe and samarium(II) iodide are generally compounds of Samarium. There is no significant biological role which can be found in Samarium, but only Samarium is slightly a toxic element. 


Uses Of Samarium 

What is Samarium used for can be explained as:

  • Samarium-Cobalt magnets which have a very high permanent magnetization is one of the most critical applications of Samarium. These magnets can be seen used in headphones, small motors and musical instruments like guitars.

  • In the manufacturing of solar-powered electric aircraft, this element can be seen.

  • In the making of special infrared absorbing glass and cores of carbon arc lamp electrodes, are considered as uses of Samarium.

  • It also acts as a catalyst in the ethanol dehydration process as well as uses of Samarium can be making new permanent magnets.


Properties Of Samarium 

Physical Properties Of Samarium 

Samarium is a rare earth metal having a hardness and thickness like those of zinc. With a boiling point of 1794 °C, Samarium is the third most volatile lanthanide after ytterbium and europium; this property encourages detachment of Samarium from the mineral ore. At surrounding conditions, Samarium typically accepts a rhombohedral structure (α form). After warming to 731 °C, its crystal symmetry changes into hexagonally close-packed (hcp), anyway the progress temperature relies upon the metal immaculateness. Further warming to 922 °C changes the metal into a body-centred cubic (bcc) stage. Warming to 300 °C joined with pressure to 40 kbar brings about a twofold hexagonally close-packed structure (dhcp). Samarium electron configuration is [Xe] 4f66s2. and Samarium atomic mass is 150.36 u.


Chemical Properties Of Samarium 

Newly prepared Samarium has a silvery radiance. In the air, it gradually oxidized at room temperature and suddenly ignites at 150 °C. In any point, when put away under mineral oil, samarium bit by bit oxidizes and builds up a greyish-yellow powder of the oxide-hydroxide blend at the surface. The metallic appearance of an example can be safeguarded via fixing it under inert gas, for example, argon. 

Samarium is very electropositive and responds gradually with cold water and rapidly with hot water to shape samarium hydroxide: 

2Sm(OH)3 (aq) + 3H2 (g) → 2Sm (s) + 6H2O (l) 

Samarium disintegrates promptly in dilute sulfuric acid to shape solutions containing the yellow to light green Sm(III) ions, which exist as [Sm(OH2)9]3+ complexes: 

2Sm (s) + 3 H2SO4 (aq) → 2 Sm3+ (aq) + 3 S(aq) + 3 H2 (g) 

One of the few lanthanides is samarium that exhibit the +2 oxidation state. The Sm2+ particles are dark red in fluid solution.


Compounds Of Samarium 

Oxides

Sesquioxide Sm2O3 is the most stable oxide of the Sm element. It exists in several crystalline phases, as many other samarium compounds. The trigonal form is obtained by slow cooling of the melt. 


Chalcogenides

Sm element forms trivalent sulfide, telluride and selenide. Divalent Chalcogenides SmS, SmSe and SmTe with cubic rock salt crustal structure are also known. By converting from semiconducting to metallic state at room temperature upon application of pressure is what Chalcogenides of the Sm element are known for.

Halides

Sm element reacts with all the halogens, forming trihalides.

2 Sm (s) + 3 X2 (g) → 2 SmX3 (s) (X = F, Cl, Br or I)

The further reduction with Samarium, lithium or sodium metals at elevated temperatures (about 700–900 °C) yields dihalides. The reduction also produces numerous non-stoichiometric samarium halides with crystal structure adding with the dihalides, such as Sm3F7, Sm14F33, Sm27F64, Sm11Br24, Sm5Br11 and Sm6Br13.


Solved Examples 

  1. About 1016 years is taken for just half the samarium-149 in nature to decay by alpha-particle emission. Explain the decay equation and isotope that is produced by the reaction?

For samarium-149, the atomic number of Samarium is equal to 62 and a mass number is equal to 149. This means 

149=b+4→ mass number conservation

62=a+2→ change conservation

You will get

b=149−4=145

a=62−2=60

The element that has an atomic number equal to 60 is neodymium, Nd.

Neodymium-145 will be produced by the alpha decay of samarium-149 and an alpha particle.

62149Sm ---> 60145Nd + 24He


Fun Fact 

  1. Uses of Samarium have no biological role, and it is not that toxic. It is observed that some soluble salts are mildly toxic but cannot affect the human life.

  2. Samarium is said to be the hardest member of the cerium group of earth metals.

  3. Samarium has a bright silver metallic lustre. 

  4. The origin of the name of Samarium is from smarskite, which is a mineral.

FAQs on Samarium Element in Chemistry

1. What is samarium?

Samarium is a chemical element with the symbol Sm and atomic number 62, belonging to the lanthanide series of rare earth elements. It is a silvery-white metal that tarnishes in air and is moderately hard and brittle. Key facts about samarium include:

  • Period: 6
  • Group: Lanthanides (f-block)
  • Electronic configuration: [Xe] 4f6 6s2
  • Common oxidation state: +3 (also +2)
Samarium is widely used in magnets, nuclear reactors, and specialized alloys.

2. What is the electron configuration of samarium?

The electron configuration of samarium (Sm) is [Xe] 4f6 6s2. This means:

  • It has 62 electrons in total.
  • The inner electrons correspond to the noble gas core xenon (Xe).
  • The outer electrons occupy the 4f and 6s subshells.
The partially filled 4f orbitals are responsible for samarium’s magnetic properties and its characteristic oxidation states.

3. What are the common oxidation states of samarium?

The most common oxidation state of samarium is +3, although it can also exhibit a stable +2 state. In compounds:

  • Sm3+ forms most typical salts such as SmCl3 and Sm2O3.
  • Sm2+ appears in reducing environments, such as in SmCl2.
The +3 state is more stable due to the removal of three valence electrons (two 6s and one 4f).

4. How does samarium react with oxygen?

Samarium reacts with oxygen to form samarium(III) oxide, Sm2O3. The balanced chemical equation is:
4Sm(s) + 3O2(g) → 2Sm2O3(s)

  • The reaction occurs when samarium is heated in air.
  • The oxide formed is a pale yellow solid.
  • This reaction shows samarium’s typical +3 oxidation state.
Like other lanthanides, samarium readily oxidizes when exposed to air.

5. What is samarium used for?

Samarium is mainly used in permanent magnets, nuclear reactors, and specialized alloys. Important applications include:

  • Samarium–cobalt (SmCo) magnets, which are strong and heat-resistant.
  • Samarium-149, used as a neutron absorber in nuclear reactors.
  • Optical lasers and infrared absorbing glass.
These uses rely on samarium’s magnetic, nuclear, and electronic properties.

6. Why is samarium considered a rare earth element?

Samarium is called a rare earth element because it belongs to the lanthanide series and occurs dispersed in minerals rather than in concentrated deposits. Although not extremely scarce, it is:

  • Found in minerals such as monazite and bastnäsite.
  • Difficult to separate due to similar chemical properties among lanthanides.
The term “rare earth” refers to extraction difficulty rather than actual rarity in Earth’s crust.

7. What is the atomic mass of samarium?

The atomic mass of samarium is approximately 150.36 u. This value represents the weighted average of its naturally occurring isotopes. Important points:

  • Samarium has several stable isotopes, including Sm-144, Sm-147, and Sm-152.
  • The atomic mass is used in molar mass calculations (150.36 g·mol-1).
This value is essential for stoichiometric calculations involving samarium compounds.

8. How does samarium react with water?

Samarium reacts slowly with cold water and more rapidly with hot water to form samarium hydroxide and hydrogen gas. The balanced equation is:
2Sm(s) + 6H2O(l) → 2Sm(OH)3(aq) + 3H2(g)

  • This reaction shows samarium forming the +3 oxidation state.
  • Hydrogen gas is released.
  • The reaction is similar to other reactive lanthanide metals.

9. What type of element is samarium in the periodic table?

Samarium is an f-block inner transition metal in the lanthanide series of the periodic table. Its classification includes:

  • Block: f-block
  • Period: 6
  • Category: Rare earth metal
Lanthanides like samarium are characterized by the filling of 4f orbitals and similar chemical reactivity.

10. What is samarium-cobalt and why is it important?

Samarium–cobalt is a type of high-strength permanent magnet alloy made from samarium and cobalt. Common compositions include SmCo5 and Sm2Co17. Key features are:

  • Very high magnetic strength.
  • Excellent resistance to heat and corrosion.
  • Used in aerospace, electric motors, and headphones.
Its importance comes from combining samarium’s magnetic properties with cobalt’s stability to produce durable, high-performance magnets.