Samarium (Sm)
lanthanideSolid
Bobot Atom Standar
150,36 uKonfigurasi elektron
[Xe] 6s2 4f6Titik lebur
1073,85 °CTitik didih
1793,85 °CMassa jenis
7520 kg/m³Bilangan oksidasi
0, +1, +2, +3Keelektronegatifan (Pauling)
1,17Energi ionisasi (ke-1)
5,643722 eVTahun penemuan
1878Jari-jari atom
185 pmDetail
Samarium is a lanthanide metal with atomic number 62. It is a typical rare-earth element in its trivalent chemistry, but it is also notable for accessible divalent compounds and for the strong neutron-absorbing isotope ¹⁴⁹Sm. The element occurs with other light rare earths in minerals such as monazite and bastnäsite. Its technological importance is concentrated in permanent magnets, neutron control, phosphors, and specialized chemical reducing agents.
Samarium has a bright silver luster and is reasonably stable in air. Three crystal modifications of the metal exist, with transformations at 734 and 922°C. The metal ignites in air at about 150°C. The sulfide has excellent high-temperature stability and good thermoelectric efficiencies up to 1100°C.
The name derives from the mineral samarskite, in which it was found and that had been named for Colonel Samarski, a Russian mine official. Samarium was originally discovered in 1878 by the Swiss chemist Marc Delafontaine, who called it decipium. It was also discovered by the French chemist Paul-Emile Lecoq de Boisbaudran in 1879. In 1881, Delafontaine determined that his decipium could be resolved into two elements, one of which was identical to Boisbaudran's samarium. In 1901, the French chemist Eugène-Anatole Demarçay showed that this samarium earth also contained europium.
Samarium was observed spectroscopically by Jean Charles Galissard de Marignac, a Swiss chemist, in a material known as dydimia in 1853. Paul-Émile Lecoq de Boisbaudran, a French chemist, was the first to isolate samarium from the mineral samarskite ((Y, Ce, U, Fe)3(Nb, Ta, Ti)5O16) in 1879. Today, samarium is primarily obtained through an ion exchange process from monazite sand ((Ce, La, Th, Nd, Y)PO4), a material rich in rare earth elements that can contain as much as 2.8% samarium.
Discovered spectroscopically by its sharp absorption lines in 1879 by Lecoq de Boisbaudran in the mineral samarskite, named in honor of a Russian mine official, Col. Samarski.
Pure samarium is a silvery, moderately hard metal that tarnishes in air as oxide forms on the surface. It has the close-packed metallic character typical of lanthanides and is normally handled as ingots, pieces, powder, or alloy feedstock under conditions that limit oxidation.
The largest distinctive use of samarium is in samarium-cobalt permanent magnets, mainly SmCo₅ and Sm₂Co₁₇, which retain magnetization at higher temperatures and resist corrosion better than many neodymium magnets. ¹⁴⁹Sm is an effective neutron absorber and samarium compounds are used in control materials and reactor physics applications. Samarium-doped materials serve in some phosphors, lasers, and infrared-absorbing glasses. Samarium(II) iodide, SmI₂, is an important one-electron reducing reagent in organic synthesis.
Samarium is one of the rare earth elements used to make carbon arc lights which are used in the motion picture industry for studio lighting and projector lights. Samarium also makes up about 1% of Misch metal, a material that is used to make flints for lighters.
Samarium forms a compound with cobalt (SmCo5) which is a powerful permanent magnet with the highest resistance to demagnetization of any material known. Samarium oxide (Sm2O3) is added to glass to absorb infrared radiation and acts as a catalyst for the dehydration and dehydrogenation of ethanol (C2H6O).
Samarium, along with other rare earths, is used for carbon-arc lighting for the motion picture industry. SmCo5 has been used in making a new permanent magnet material with the highest resistance to demagnetization of any known material. It is said to have an intrinsic coercive force as high as 2200 kA/m. Samarium oxide has been used in optical glass to absorb the infrared. Samarium is used to dope calcium fluoride crystal for use in optical lasers or lasers. Compounds of the metal act as sensitizers for phosphors excited in the infrared; the oxide exhibits catalytic properties in the dehydration and dehydrogenation of ethyl alcohol. It is used in infrared absorbing glass and as a neutron absorber in nuclear reactors.
Isotopes in Earth/Planetary Science
One possible origin for the Moon is from debris ejected by an indirect giant impact of Earth by an astronomical body the size of Mars when the Earth was forming [436] R. M. Canup, E. Asphaug. Nature412, 708 (2001).. The kinetic energy liberated is thought to have melted a large part of the Moon forming a lunar magma ocean. Samarium isotope measurement results [437] A. Brandon. Nature450, 1169 (2007)., along with measurements of isotopes of hafnium, tungsten, and neodymium [438] K. Righter, C. K. Shearer. Geochim. Cosmochim. Acta67, 2497 (2003)., suggest that lunar magma formed about 70×106 years after the Solar System formed and had crystallized by about 215×106 years after formation. 147Sm (with a half-life of 1.06×1011 years) is used to study the formation of potassium, rare earth elements, and phosphorus-rich rocks [439] J. Edmunson, L. E. Borg. “The formation age of KREEP based on the 147Sm-143Nd geochemistry of KREEP-rich rocks: duration of lunar magma ocean crystallization and similarity to early mars”, in Workshop on Early Planetary Differentiation..
Isotopes in Geochronology
147Sm is used for determining formation ages of igneous and metamorphic rocks via analysis of the minerals which compose them, such as those shown in Fig. IUPAC.62.1 [440] T. Iizuka, O. Nebel, M. McCulloch. Early Crustal Evolution Deduced from a Combined U-Pb and Sm-Nd Isotopic Study of Mt. Narryer and Jack Hills Monazites, The Australian National University (2014), Feb. 28; http://rses.anu.edu.au/highlights/view.php?article=191., [441] K. Rankenburg, A. D. Brandon, C. R. Neal. Science312 1369 (2006)., [442] F. F. Hu, H. R. Fan, S. Liu, K. F. Yang, F. Chen. Resour. Geol.59, 407 (2009)..
Isotopes in Medicine
The radioisotope 153Sm (with a half-life of 1.9 days) is used in medicine to treat the severe pain associated with cancer that has spread to bones (Fig. IUPAC.62.2) [443] International Atomic Energy Agency. Optimization of Production and Quality Control of Therapeutic Radionuclides and Radiopharmaceuticals, IAEA-TECDOC-1114, IAEA VIENNA (1999)., [444] C. L. Maini, S. Bergomi, L. Romano, R. Sciuto. Eur. J. Nucl. Med. Mol. Imaging31, S171 (2004)., [445] N. Pandit-Taskar, M. Batraki, C. R. Divgi. J. Nucl. Med.45, 1358 (2004)..
Isotopes Used as a Source of Radioactive Isotope(s)
147Sm bombarded with 40Ca produces the radioisotope 182Pb [446] K. S. Toth, D. M. Moltz, J. M. Nitschke, P. A. Wilmarth, J. D. Robertson. AIP Conference Proc.283, 347 (1991)..
Samarium most commonly forms Sm³⁺ salts and oxides. Samarium(III) oxide, Sm₂O₃, is a stable sesquioxide used as a starting material for many other compounds. Halides such as samarium(III) chloride, SmCl₃, and samarium(III) fluoride, SmF₃, are typical ionic rare-earth salts. The Sm²⁺ state is less common but chemically important; samarium(II) iodide, SmI₂, is a mild, selective reductant, and samarium(II) sulfide, SmS, shows pressure-sensitive electronic behavior. Mixed-valence chemistry is known in some solids.
See more information at the Samarium compound page.
Compact samarium metal has low acute toxicity, but finely divided metal can burn and should be kept from ignition sources. Dusts and soluble samarium salts may irritate tissues and should not be inhaled or ingested. Natural samarium is weakly radioactive because of long-lived isotopes, especially ¹⁴⁷Sm and ¹⁴⁸Sm, but its specific activity is low. Reactor-produced or isotope-enriched materials can present additional radiation hazards depending on isotopic composition.
Little is known of the toxicity of samarium; therefore, it should be handled carefully.
Samarium is dispersed in the crust as a minor component of rare-earth minerals rather than as native metal. In soils and waters it is generally present as Sm³⁺ associated with phosphates, carbonates, oxides, and organic ligands. It is not known to have an essential biological role. Mining and processing can mobilize samarium together with other rare earths and, in monazite deposits, with thorium and uranium by-products.
Samarium is produced as part of rare-earth separation rather than from samarium-specific ores. Concentrates from monazite and bastnäsite are chemically processed, and individual rare earths are separated by solvent extraction or ion-exchange methods before conversion to oxides, metals, or alloys. Demand is much smaller than for cerium, lanthanum, or neodymium, but it is strategically important where high-temperature Sm-Co magnets are required. Recycling is limited compared with primary production, partly because samarium is often present in durable, specialized magnet assemblies.
Samarium is found along with other members of the rare-earth elements in many minerals, including monazite and bastnasite, which are commercial sources. It occurs in monazite to the extent of 2.8%. While misch metal containing about 1% of samarium metal, has long been used, samarium has not been isolated in relatively pure form until recently. Ion-exchange and solvent extraction techniques have recently simplified separation of the rare earths from one another; more recently, electrochemical deposition, using an electrolytic solution of lithium citrate and a mercury electrode, is said to be a simple, fast, and highly specific way to separate the rare earths. Samarium metal can be produced by reducing the oxide with lanthanum.
Samarium is a heavy element made mainly by neutron-capture processes in earlier generations of stars. Its stable and long-lived isotopes reflect contributions from both slow and rapid neutron-capture nucleosynthesis. In planetary materials it is lithophile and follows other rare earths into refractory minerals, making samarium-neodymium isotope systematics useful in geochemistry and cosmochemistry.
- Samarium was named from the mineral samarskite, which was itself named after Vasili Samarsky-Bykhovets.
- ¹⁴⁷Sm decays very slowly to ¹⁴³Nd and is used in Sm-Nd radiometric dating.
- ¹⁴⁹Sm has one of the largest thermal-neutron capture cross sections among naturally occurring nuclides.
- Samarium-cobalt magnets preceded modern neodymium-iron-boron magnets in many high-performance applications.
- SmS can change from a black semiconducting phase toward a golden metallic state under pressure.
Gambar
Sifat
Fisika
- Jari-jari atom (empiris)
- 185 pm Bandingkan Jari-jari atom (empiris) semua unsur →
- Jari-jari kovalen
- 198 pm Bandingkan Jari-jari kovalen semua unsur →
- Jari-jari van der Waals
- 229 pm Bandingkan Jari-jari van der Waals semua unsur →
- Massa jenis
- 7520 kg/m³ Bandingkan Massa jenis semua unsur →
- Volume molar
- 0,0199 L/mol
- Fase pada STP
- Padat Bandingkan Fase pada STP semua unsur →
- Titik lebur
- 1073,85 °C Bandingkan Titik lebur semua unsur →
- Titik didih
- 1793,85 °C Bandingkan Titik didih semua unsur →
- Kapasitas kalor spesifik
- 0,197 J/(g·K) Bandingkan Kapasitas kalor spesifik semua unsur →
- Kapasitas kalor molar
- 29,54 J/(mol·K) Bandingkan Kapasitas kalor molar semua unsur →
- Struktur kristal
- Rombohedral Bandingkan Struktur kristal semua unsur →
Kimia
- Keelektronegatifan (Pauling)
- 1,17 Bandingkan Keelektronegatifan (Pauling) semua unsur →
- Afinitas elektron
- 0,156 eV
- Energi ionisasi (ke-1)
- 5,643722 eV Bandingkan Energi ionisasi (ke-1) semua unsur →
- Energi ionisasi (ke-2)
- 11,078038 eV Bandingkan Energi ionisasi (ke-2) semua unsur →
- Energi ionisasi (ke-3)
- 23,550081 eV Bandingkan Energi ionisasi (ke-3) semua unsur →
- Energi ionisasi (ke-4)
- 41,640143 eV Bandingkan Energi ionisasi (ke-4) semua unsur →
- Energi ionisasi (ke-5)
- 62,700216 eV Bandingkan Energi ionisasi (ke-5) semua unsur →
- Bilangan oksidasi
- 0, +1, +2, +3 Bandingkan Bilangan oksidasi semua unsur →
- Elektron valensi
- 3 Bandingkan Elektron valensi semua unsur →
- Konfigurasi elektron
- [Xe] 6s2 4f6
Termodinamika
- Kalor peleburan
- 0,08934031 eV Bandingkan Kalor peleburan semua unsur →
- Kalor penguapan
- 1,71011 eV Bandingkan Kalor penguapan semua unsur →
- Kalor sublimasi
- 2,145411 eV
- Kalor atomisasi
- 2,145411 eV
- Entalpi atomisasi
- 2,142302 eV
Nuklir
- Proton
- 62 Bandingkan Proton semua unsur →
- Neutron
- 90 Bandingkan Neutron semua unsur →
- Isotop yang diketahui
- 41 Bandingkan Isotop yang diketahui semua unsur →
- Isotop stabil
- 3 Bandingkan Isotop stabil semua unsur →
- Isotop paling stabil
- Sm-152
- Tahun penemuan
- 1878
Kelimpahan
- Kelimpahan (kerak Bumi)
- 7,05 mg/kg Bandingkan Kelimpahan (kerak Bumi) semua unsur →
- Kelimpahan (samudra)
- 4,5 × 10−7 mg/L Bandingkan Kelimpahan (samudra) semua unsur →
Struktur Kristal
- Konstanta kisi a
- 900 pm
Struktur Elektronik
- Elektron per kulit
- 2, 8, 18, 24, 8, 2 Bandingkan Elektron per kulit semua unsur →
Pengenal
- Nomor CAS
- 7440-19-9 Bandingkan Nomor CAS semua unsur →
- Simbol term
- 7F0
- InChI
- InChI=1S/Sm
- Kunci InChI
- KZUNJOHGWZRPMI-UHFFFAOYSA-N
Konfigurasi Elektron Diukur
Sm: 4f⁶ 6s²[Xe] 4f⁶ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f⁶ 6s²Model atom
Isotop mengubah jumlah neutron, massa, dan kestabilan — bukan konfigurasi elektron atom netral.
Model atom skematis, tidak sesuai skala.
Sidik Jari Atom
Spektrum Emisi / Absorpsi
Distribusi Isotop
| Nomor massa | Massa atom (u) | Kelimpahan alami | Waktu paruh |
|---|---|---|---|
| 144 Stabil | 143,9120065 ± 0,0000021 | 3,0700% | Stabil |
| 150 Stabil | 149,9172829 ± 0,0000018 | 7,3800% | Stabil |
| 152 Stabil | 151,9197397 ± 0,0000018 | 26,7500% | Stabil |
Fase / Wujud
Alasan: 1048,8 °C di bawah titik lebur (1073,85 °C)
Skematis, tidak sesuai skala
Titik transisi fase
Energi transisi
Energi yang diperlukan untuk meleburkan 1 mol pada titik lebur
Energi yang diperlukan untuk menguapkan 1 mol pada titik didih
Energi yang diperlukan untuk menyublimkan 1 mol pada titik sublimasi
Massa jenis
Pada kondisi standar
Pada kondisi standar
Spektrum Atom
Menampilkan 10 dari 62. Diurutkan berdasarkan muatan ion (menaik).
Data Garis Spektrum ?
| Ion | Muatan | Total garis | Probabilitas transisi | Penamaan tingkat energi |
|---|---|---|---|---|
| Sm I | 0 | 162 | 7 | 11 |
| Sm II | +1 | 635 | 7 | 14 |
Data Tingkat Energi ?
| Ion | Muatan | Tingkat energi |
|---|---|---|
| Sm I | 0 | 501 |
| Sm II | +1 | 377 |
| Sm III | +2 | 58 |
| Sm IV | +3 | 24 |
| Sm V | +4 | 2 |
| Sm VI | +5 | 2 |
| Sm VII | +6 | 2 |
| Sm VIII | +7 | 2 |
| Sm IX | +8 | 2 |
| Sm X | +9 | 2 |
Data struktur kristal tidak tersedia
Struktur kristal: rhombohedral
Jari-jari Ion
| Muatan | Koordinasi | Spin | Jari-jari |
|---|---|---|---|
| +2 | 7 | Tidak tersedia | 122 pm |
| +2 | 8 | Tidak tersedia | 127 pm |
| +2 | 9 | Tidak tersedia | 132 pm |
| +3 | 6 | Tidak tersedia | 95.8 pm |
| +3 | 7 | Tidak tersedia | 102 pm |
| +3 | 8 | Tidak tersedia | 107.89999999999999 pm |
| +3 | 9 | Tidak tersedia | 113.19999999999999 pm |
| +3 | 12 | Tidak tersedia | 124 pm |
Senyawa
Isotop (3)
Twenty one isotopes of samarium exist. Natural samarium is a mixture of several isotopes, three of which are unstable with long half-lives.
| Nomor massa | Massa atom (u) | Kelimpahan alami | Waktu paruh | Mode peluruhan | |
|---|---|---|---|---|---|
| 144 Stabil | 143,9120065 ± 0,0000021 | 3,0700% ± 0,0700% | Stabil | stable | |
| 150 Stabil | 149,9172829 ± 0,0000018 | 7,3800% ± 0,0100% | Stabil | stable | |
| 152 Stabil | 151,9197397 ± 0,0000018 | 26,7500% ± 0,1600% | Stabil | stable |
Sifat Lanjutan
Jari-jari Kovalen (Lanjutan)
- Jari-jari kovalen (Pyykkö)
- 172 pm
- Jari-jari kovalen (Pyykkö, ikatan rangkap dua)
- 134 pm
Jari-jari van der Waals
- Alvarez
- 290 pm
- UFF
- 352 pm
- MM3
- 271 pm
Jari-jari Atom & Logam
- Jari-jari atom (Rahm)
- 280 pm
Skala Penomoran
- Mendeleev
- 23
- Pettifor
- 28
- Glawe
- 27
Skala Keelektronegatifan
- Ghosh
- 0
- Miedema
- 3
- Gunnarsson–Lundqvist
- 6
- Robles–Bartolotti
- 5
Polarizabilitas & Dispersi
- Polarizabilitas dipol
- 192 a.u.
- Polarizabilitas dipol (ketidakpastian)
- 20 a.u.
- C₆ (Gould–Bučko)
- 3130 Ha·Bohr6
Parameter Miedema
- Volume molar Miedema
- 20,01 cm3/mol
- Kerapatan elektron Miedema
- 2
Risiko Pasokan & Ekonomi
- Konsentrasi produksi
- 97
- Risiko pasokan relatif
- 10
- Distribusi cadangan
- 50
- Stabilitas politik (produsen terbesar)
- 24
- Stabilitas politik (pemilik cadangan terbesar)
- 24
Transisi Fase & Alotrop
| Titik lebur | 1345,15 K |
| Titik didih | 2067,15 K |
Kategori Bilangan Oksidasi
Data Referensi Lanjutan
Konstanta Pemerisaian (13)
| n | Orbital | σ |
|---|---|---|
| 1 | s | 1,2217 |
| 2 | p | 4,269 |
| 2 | s | 16,2652 |
| 3 | d | 13,7711 |
| 3 | p | 19,5815 |
| 3 | s | 19,9736 |
| 4 | d | 33,7604 |
| 4 | f | 38,4684 |
| 4 | p | 30,912 |
| 4 | s | 29,7076 |
Detail Jari-jari Kristal (8)
| Muatan | CN | Spin | rcrystal (pm) | Asal |
|---|---|---|---|---|
| 2 | VII | 136 | ||
| 2 | VIII | 141 | ||
| 2 | IX | 146 | ||
| 3 | VI | 109,8 | from r^3 vs V plots, | |
| 3 | VII | 116 | estimated, | |
| 3 | VIII | 121,9 | from r^3 vs V plots, | |
| 3 | IX | 127,2 | from r^3 vs V plots, | |
| 3 | XII | 138 | calculated, |
Mode Peluruhan Isotop (52)
| Isotop | Mode | Intensitas |
|---|---|---|
| 128 | B+ | — |
| 128 | B+p | — |
| 129 | B+ | 100% |
| 129 | B+p | — |
| 130 | B+ | — |
| 131 | B+ | 100% |
| 131 | B+p | — |
| 132 | B+ | 100% |
| 132 | B+p | — |
| 133 | B+ | 100% |
Faktor Hamburan Sinar-X (508)
| Energi (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0,18764 |
| 10,1617 | — | 0,19534 |
| 10,3261 | — | 0,20334 |
| 10,4931 | — | 0,21168 |
| 10,6628 | — | 0,22036 |
| 10,8353 | — | 0,22939 |
| 11,0106 | — | 0,2388 |
| 11,1886 | — | 0,24859 |
| 11,3696 | — | 0,25878 |
| 11,5535 | — | 0,26939 |
Data Tambahan
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
7.05 milligrams per kilogram
Referensi (1)
- [5] Samarium https://education.jlab.org/itselemental/ele062.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
4.5×10-7 milligrams per liter
Referensi (1)
- [5] Samarium https://education.jlab.org/itselemental/ele062.html
Sources
Sources of this element.
Samarium is found along with other members of the rare-earth elements in many minerals, including monazite and bastnasite, which are commercial sources. It occurs in monazite to the extent of 2.8%. While misch metal containing about 1% of samarium metal, has long been used, samarium has not been isolated in relatively pure form until recently. Ion-exchange and solvent extraction techniques have recently simplified separation of the rare earths from one another; more recently, electrochemical deposition, using an electrolytic solution of lithium citrate and a mercury electrode, is said to be a simple, fast, and highly specific way to separate the rare earths. Samarium metal can be produced by reducing the oxide with lanthanum.
Referensi (1)
- [6] Samarium https://periodic.lanl.gov/62.shtml
Referensi
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/
The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.
The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database
This section provides all form of data related to element Samarium.
The element property data was retrieved from publications.