What Makes Samarium Important in Chemistry?
What is Samarium?
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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
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
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.
Samarium is said to be the hardest member of the cerium group of earth metals.
Samarium has a bright silver metallic lustre.
The origin of the name of Samarium is from smarskite, which is a mineral.
FAQs on Samarium: Properties, Uses, and Compounds
1. What is samarium and where is it found in nature?
Samarium (symbol Sm, atomic number 62) is a moderately hard, silvery-white rare earth element belonging to the lanthanide series of the periodic table. It is not found free in nature but is primarily obtained from minerals such as monazite, bastnäsite, and samarskite. These ores are mined in countries like China, the USA, Brazil, India, and Australia.
2. What are the key physical and chemical properties of samarium?
Samarium has several distinct properties that are important for students to know:
Appearance: It is a silvery-white metal.
Atomic Mass: Approximately 150.36 u.
Melting Point: 1072 °C (1345 K).
Boiling Point: 1794 °C (2067 K).
Reactivity: Samarium is quite reactive. It slowly oxidises in air and reacts slowly with cold water and more quickly with hot water to form samarium hydroxide.
3. What is the electron configuration of samarium and what does it indicate?
The electron configuration of samarium is [Xe] 4f⁶ 6s². This configuration is significant because it explains samarium's common oxidation states. It most readily loses its two 6s electrons and one 4f electron to achieve a stable +3 oxidation state (Sm³⁺), which is typical for lanthanides. However, it can also exhibit a +2 oxidation state (Sm²⁺) by losing only the two 6s electrons, which is relatively stable compared to many other lanthanides.
4. What are the most important uses of samarium?
Samarium has several critical applications in modern technology and industry. Its most important uses include:
Permanent Magnets: Samarium-cobalt (SmCo₅ and Sm₂Co₁₇) magnets are powerful and resistant to very high temperatures, making them essential in motors, generators, and aerospace applications.
Nuclear Reactors: It is an excellent neutron absorber, used in control rods of nuclear reactors to manage the fission process.
Catalysis: Samarium compounds act as catalysts in various organic chemical reactions, such as dehydration and dehydrogenation of ethanol.
Specialised Lighting: It is used in carbon arc lights for studio lighting and projectors in the motion picture industry.
5. What are some common compounds of samarium and their oxidation states?
The chemistry of samarium is dominated by the +3 oxidation state. The most common compound is Samarium(III) oxide (Sm₂O₃), a pale yellow powder. Other important compounds include its halides, such as Samarium(III) chloride (SmCl₃) and Samarium(III) fluoride (SmF₃). Compounds in the +2 state, like Samarium(II) iodide (SmI₂), also exist and are used as reducing agents in chemical synthesis.
6. Why are samarium-cobalt magnets so powerful and resistant to high temperatures?
Samarium-cobalt magnets derive their strength from the combination of samarium's high magnetic anisotropy and cobalt's ferromagnetic properties. This structure creates a material that strongly resists being demagnetised. Their key advantage is a very high Curie temperature (above 700°C), which is the temperature at which a material loses its permanent magnetic properties. This allows them to function effectively in high-temperature environments like electric motors and military guidance systems, where other powerful magnets like neodymium magnets would fail.
7. How is the radioactive isotope samarium-153 used in medicine?
The radioactive isotope samarium-153 is a key component in a radiopharmaceutical drug used for cancer treatment. It is used for the palliative care of bone pain in patients whose cancer has metastasised to the bone. Samarium-153 emits beta particles, which are short-range and effective at killing nearby cancer cells, thereby reducing pain. It also emits gamma rays, which can be detected by a gamma camera to ensure the drug has been delivered to the correct locations in the skeleton.
8. How does samarium's position as a lanthanide affect its chemical behaviour?
As a member of the lanthanide series, samarium's chemical behaviour is heavily influenced by its position. Its properties are very similar to its neighbouring elements, making it difficult to separate from them during extraction. A key characteristic it exhibits is the lanthanide contraction—a gradual decrease in atomic and ionic radii across the series. This contraction makes its ionic radius (for Sm³⁺) very similar to that of heavier elements, influencing its coordination chemistry. The dominant +3 oxidation state is a defining feature of all lanthanides, arising from the stability gained by losing the outer 6s and one 4f or 5d electron.
9. What makes samarium different from other rare earth elements like neodymium or europium?
While chemically similar, samarium has key differences from other lanthanides. Compared to neodymium (Nd), samarium is used in magnets (SmCo) that are more heat-resistant, whereas neodymium magnets (NdFeB) are stronger at room temperature but lose magnetism at lower temperatures. Compared to europium (Eu), samarium's +2 oxidation state is less stable. Europium readily forms a stable Eu²⁺ ion due to its half-filled 4f⁷ electron shell, making it a strong reducing agent. Samarium's Sm²⁺ ion is also a reducing agent but is less stable and powerful than Eu²⁺. These subtle differences in oxidation state stability and magnetic properties lead to their distinct applications.
