SAMARIO

Introducción

Número atómico: 62
Grupo: Ninguna
Peso atomico: 150.36
Período: 6
Número CAS: 7440-19-9

Clasificación

chalcogen
halógeno
Gas noble
Lantanoides
Actinoides
Elemento de tierras raras
Platino Metal Group
transuranium
No hay isótopos estables
Sólido
Líquido
Gas
Sólido (Predicho)

Descripción • Usos / Función

Discovered spectroscopically by its sharp absorption lines in 1879 by Lecoq de Boisbaudran in the mineral samarskite, named in honor of a Russianmine official, Col. Samarski. Samarium is found along with other members of the rare-earth elements in many minerals, including monazite andbastnasite, 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 recent years. Ion-exchange and solvent extraction techniques haverecently simplified separation of the rare earths from one another; more recently, electrochemical deposition, using an electrolytic solution of lithiumcitrate 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 byreducing the oxide with barium or lanthanum. Samarium has a bright silver luster and is reasonably stable in air. Three crystal modifications of themetal exist, with transformations at 734 and 922°C. The metal ignites in air at about 150°C. Thirty two isotopes and isomers of samarium are nowrecognized. Natural samarium is a mixture of seven isotopes, three of which are unstable but have long half-lives. Samarium, along with other rareearths, is used for carbon-arc lighting for the motion picture industry. The sulfide has excellent high-temperature stability and good thermoelectricefficiencies up to 1100°C. SmCo5 has been used in making a new permanent magnet material with the highest resistance to demagnetization of anyknown 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 crystals for use in optical masers or lasers. Compounds of the metal act as sensitizers for phosphors excitedin the infrared; the oxide exhibits catalytic properties in the dehydration and dehydrogenation of ethyl alcohol. It is used in infrared absorbing glassand as a neutron absorber in nuclear reactors. The metal is priced at about $2/g (99.9%). Little is known of the toxicity of samarium; therefore, it shouldbe handled carefully. 1

• "Samarium magnets, which can withstand intense heat, help control Predator drones and Tomahawk cruise missiles." 2

Propiedades físicas

Punto de fusion:3*  1074 °C = 1347.15 K = 1965.2 °F
Punto de ebullición:3* 1794 °C = 2067.15 K = 3261.2 °F
Punto de sublimación:3 
Triple punto:3 
Punto crítico:3 
Densidad:4  7.52 g/cm3

* - at 1 atm

Configuración electronica

Configuración electronica:  *[Xe] 6s2 4f6
Bloquear: f
Ocupado más alto nivel de energía: 6
Electrones de valencia: 2

Números cuánticos:

n = 4
ℓ = 3
m = 2
ms = +½

Vinculación

electronegatividad (escala de Pauling):5 1.17
Electropositivity (escala de Pauling): 2.83
Función del trabajo:6 2.95 eV = 4.7259E-19 J

potencial de ionización   eV 7  kJ/mol  
1 5.6436    544.5
potencial de ionización   eV 7  kJ/mol  
2 11.07    1068.1
potencial de ionización   eV 7  kJ/mol  
3 23.4    2257.8
4 41.4    3994.5

termoquímica

Calor especifico: 0.197 J/g°C 8 = 29.621 J/mol°C = 0.047 cal/g°C = 7.080 cal/mol°C
Conductividad térmica: 13.3 (W/m)/K, 27°C 9
Calor de fusión: 8.63 kJ/mol 10 = 57.4 J/g
Calor de vaporización: 166.4 kJ/mol 11 = 1106.7 J/g
Estado de la materia Entalpía de formación (ΔHf°)12 entropía (S°)12 Energía libre de Gibbs (ΔGf°)12
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s) 0 0 16.63 69.57992 0 0
(g) 49.4 206.6896 43.72 182.92448 41.3 172.7992

isótopos

nucleido Masa 13 Media vida 13 spin nuclear 13 Energía de unión
128Sm 127.95808(54)# 0.5# s 0+ 1,031.20 MeV
129Sm 128.95464(54)# 550(100) ms 5/2+# 1,039.27 MeV
130Sm 129.94892(43)# 1# s 0+ 1,056.65 MeV
131Sm 130.94611(32)# 1.2(2) s 5/2+# 1,064.72 MeV
132Sm 131.94069(32)# 4.0(3) s 0+ 1,072.80 MeV
133Sm 132.93867(21)# 2.90(17) s (5/2+) 1,090.18 MeV
134Sm 133.93397(21)# 10(1) s 0+ 1,098.25 MeV
135Sm 134.93252(17) 10.3(5) s (7/2+) 1,106.33 MeV
136Sm 135.928276(13) 47(2) s 0+ 1,123.71 MeV
137Sm 136.92697(5) 45(1) s (9/2-) 1,131.78 MeV
138Sm 137.923244(13) 3.1(2) min 0+ 1,139.85 MeV
139Sm 138.922297(12) 2.57(10) min 1/2+ 1,147.93 MeV
140Sm 139.918995(13) 14.82(12) min 0+ 1,165.31 MeV
141Sm 140.918476(9) 10.2(2) min 1/2+ 1,173.38 MeV
142Sm 141.915198(6) 72.49(5) min 0+ 1,181.45 MeV
143Sm 142.914628(4) 8.75(8) min 3/2+ 1,189.53 MeV
144Sm 143.911999(3) ESTABLE 0+ 1,197.60 MeV
145Sm 144.913410(3) 340(3) d 7/2- 1,205.67 MeV
146Sm 145.913041(4) 1.03(5)E+8 a 0+ 1,213.74 MeV
147Sm 146.9148979(26) 1.06(2)E+11 a 7/2- 1,221.81 MeV
148Sm 147.9148227(26) 7(3)E+15 a 0+ 1,229.88 MeV
149Sm 148.9171847(26) ESTABLE 7/2- 1,237.95 MeV
150Sm 149.9172755(26) ESTABLE 0+ 1,246.02 MeV
151Sm 150.9199324(26) 90(8) a 5/2- 1,254.10 MeV
152Sm 151.9197324(27) ESTABLE 0+ 1,262.17 MeV
153Sm 152.9220974(27) 46.284(4) h 3/2+ 1,260.92 MeV
154Sm 153.9222093(27) ESTABLE 0+ 1,269.00 MeV
155Sm 154.9246402(28) 22.3(2) min 3/2- 1,277.07 MeV
156Sm 155.925528(10) 9.4(2) h 0+ 1,285.14 MeV
157Sm 156.92836(5) 8.03(7) min (3/2-) 1,293.21 MeV
158Sm 157.92999(8) 5.30(3) min 0+ 1,301.28 MeV
159Sm 158.93321(11) 11.37(15) s 5/2- 1,300.04 MeV
160Sm 159.93514(21)# 9.6(3) s 0+ 1,308.11 MeV
161Sm 160.93883(32)# 4.8(8) s 7/2+# 1,316.18 MeV
162Sm 161.94122(54)# 2.4(5) s 0+ 1,314.94 MeV
163Sm 162.94536(75)# 1# s 1/2-# 1,323.01 MeV
164Sm 163.94828(86)# 500# ms 0+ 1,331.08 MeV
165Sm 164.95298(97)# 200# ms 5/2-# 1,329.83 MeV
Los valores marcados con # no son puramente derivan de los datos experimentales, pero al menos en parte, de las tendencias sistemáticas. Hace girar con débiles argumentos de asignación se incluyen entre paréntesis. 13

Abundancia

Tierra - Los compuestos de origen: phosphates 14
Tierra - Agua de mar: 0.00000045 mg/L 15
Tierra -  Corteza:  7.05 mg/kg = 0.000705% 15
Tierra -  Total:  208 ppb 16
Planeta mercurio) -  Total:  160 ppb 16
Venus -  Total:  218 ppb 16
condritas - Total: 0.23 (relative to 106 atoms of Si) 17

Compuestos

Información de seguridad


Ficha de datos de seguridad de materiales - ACI Alloys, Inc.

Para más información

Enlaces externos:

revistas:
(1) Folger, Tim. The Secret Ingredients of Everything. National Geographic, June 2011, pp 136-145.

Fuentes

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:27.
(2) - Folger, Tim. The Secret Ingredients of Everything. National Geographic, June 2011, p 140.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(5) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(6) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(12) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(13) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(14) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(15) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(16) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(17) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.