Samarium

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Samarium
62Sm
-

Sm

Pu
promethiumsamariumeuropium
Appearance
sillery white
General properties
Name, seembol, nummer samarium, Sm, 62
Pronunciation /səˈmɛəriəm/ sə-MAIR-ee-əm
Element category lanthanide
Group, period, block n/a, 6, f
Staundart atomic wicht 150.36
Electron confeeguration [Xe] 6s2 4f6
2, 8, 18, 24, 8, 2
Electron shells of samarium (2, 8, 18, 24, 8, 2)
History
Namin efter the mineral samarskite (itself named efter Vasili Samarsky-Bykhovets)
Discovery Lecoq de Boisbaudran (1879)
First isolation Lecoq de Boisbaudran (1879)
Physical properties
Phase solid
Density (near r.t.) 7.52 g·cm−3
Liquid density at m.p. 7.16 g·cm−3
Meltin pynt 1345 K, 1072 °C, 1962 °F
Boilin pynt 2067 K, 1794 °C, 3261 °F
Heat o fusion 8.62 kJ·mol−1
Heat o vaporization 165 kJ·mol−1
Molar heat capacity 29.54 J·mol−1·K−1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1001 1106 1240 (1421) (1675) (2061)
Atomic properties
Oxidation states 4, 3, 2, 1

(mildly basic oxide)

Electronegativity 1.17 (Pauling scale)
Ionization energies 1st: 544.5 kJ·mol−1
2nd: 1070 kJ·mol−1
3rd: 2260 kJ·mol−1
Atomic radius 180 pm
Covalent radius 198±8 pm
Miscellanea
Crystal structure rhombohedral
Samarium has a rhombohedral crystal structure
Magnetic orderin paramagnetic[1]
Electrical resistivity (r.t.) (α, poly) 0.940 µΩ·m
Thermal conductivity 13.3 W·m−1·K−1
Thermal expansion (r.t.) (α, poly) 12.7 µm/(m·K)
Speed of sound (thin rod) (20 °C) 2130 m·s−1
Young's modulus (α form) 49.7 GPa
Shear modulus (α form) 19.5 GPa
Bulk modulus (α form) 37.8 GPa
Poisson ratio (α form) 0.274
Vickers hairdness 412 MPa
Brinell hairdness 441 MPa
CAS registry nummer 7440-19-9
Most stable isotopes
Main article: Isotopes o samarium
iso NA hauf-life DM DE (MeV) DP
144Sm 3.07% - (β+β+) 1.7811 144Nd
(α) 0.0761 140Nd
145Sm syn 340 d ε - 145Pm
146Sm trace 1.03×108 y α 2.529 142Nd
147Sm 14.99% 1.06×1011 y α 2.310 143Nd
148Sm 11.24% 7×1015 y α 1.986 144Nd
149Sm 13.82% >2×1015 y (α) 1.870 145Nd
150Sm 7.38% - (α) 1.4495 146Nd
151Sm syn 90 y β - 151Eu
152Sm 26.75% - (α) 0.2203 148Nd
153Sm syn 46.284 h β - 153Eu
154Sm 22.75% >2.3×1018 y (ββ) 1.2510 154Gd
Decay modes in parentheses are predictit, but hae nae yet been observed
· r

Samarium is a chemical element wi seembol Sm an atomic nummer 62. It is a moderately haird sillery metal that readily oxidizes in air. Bein a typical member o the lanthanide series, samarium uisually assumes the oxidation state +3. Compoonds o samarium(II) are an aa kent, maist notably the monoxide SmO, monochalcogenides SmS, SmSe an SmTe, as well as samarium(II) iodide. The last compoond is a common reducin agent in chemical synthesis. Samarium haes na signeeficant biological role an is anly slichtly toxic.

References[eedit | eedit soorce]

  1. Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.