EINSTENIO

Introducción

Número atómico: 99
Grupo: Ninguna
Peso atomico: 252
Período: 7
Número CAS: 7429-92-7

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

Einsteinium, the seventh transuranic element of the actinide series to be discovered, was identified by Ghiorso and co-workers at Berkeley in December 1952 in debris from the first large thermonuclear explosion, which took place in the Pacific in November 1952. The isotope produced was the 20-day 253Es isotope. In 1961, a sufficient amount of einsteinium was produced to permit separation of a macroscopic amount of 253Es. This sample weighed about 0.01 micrograms. A special magnetic-type balance was used in making this determination. 253Es so produced was used to produce mendelevium (Element 101). About 3 micrograms of einsteinium has been produced at Oak Ridge National Laboratories by irradiating for several years kilogram quantities of 239Pu in a reactor to produce 242Pu. This was then fabricated into pellets of plutonium oxide and aluminum powder, and loaded into target rods for an initial 1-year irradiation at the Savannah River Plant, followed by irradiation in a HFIR (High Flux Isotopic Reactor). After 4 months in the HFIR the targets were removed for chemical separation of the einsteinium from californium. Seventeen isotopes and isomers of einsteinium are now recognized. 254Es has the longest half-life (276 days). Tracer studies using 253Es show that einsteinium has chemical properties typical of a heavy trivalent, actinide element. 1

Propiedades físicas

Punto de fusion:2*  860 °C = 1133.15 K = 1580 °F
Punto de ebullición:2
Punto de sublimación:2 
Triple punto:2 
Punto crítico:2 
Densidad:   g/cm3

* - at 1 atm

Configuración electronica

Configuración electronica:  *[Rn] 7s2 5f11
Bloquear: f
Ocupado más alto nivel de energía: 7
Electrones de valencia: 2

Números cuánticos:

n = 5
ℓ = 3
m = 0
ms = -½

Vinculación

potencial de ionización   eV 3  kJ/mol  
potencial de ionización   eV 3  kJ/mol  
potencial de ionización   eV 3  kJ/mol  
1 6.42    619.4

isótopos

nucleido Masa 4 Media vida 4 spin nuclear 4 Energía de unión
240Es 240.06892(43)# 1# s 1,803.77 MeV
241Es 241.06854(24)# 10(5) s [8(+6-5) s] (3/2-) 1,811.84 MeV
242Es 242.06975(35)# 13.5(25) s 1,819.91 MeV
243Es 243.06955(25)# 21(2) s 3/2-# 1,827.99 MeV
244Es 244.07088(20)# 37(4) s 1,826.74 MeV
245Es 245.07132(22)# 1.1(1) min (3/2-) 1,834.81 MeV
246Es 246.07290(24)# 7.7(5) min 4-# 1,842.88 MeV
247Es 247.07366(3)# 4.55(26) min 7/2+# 1,850.96 MeV
248Es 248.07547(6)# 27(5) min 2-#,0+# 1,859.03 MeV
249Es 249.07641(3)# 102.2(6) min 7/2+ 1,867.10 MeV
250Es 250.07861(11)# 8.6(1) h (6+) 1,875.17 MeV
251Es 251.079992(7) 33(1) h (3/2-) 1,883.24 MeV
252Es 252.08298(5) 471.7(19) d (5-) 1,882.00 MeV
253Es 253.0848247(28) 20.47(3) d 7/2+ 1,890.07 MeV
254Es 254.088022(5) 275.7(5) d (7+) 1,898.14 MeV
255Es 255.090273(12) 39.8(12) d (7/2+) 1,896.90 MeV
256Es 256.09360(11)# 25.4(24) min (1+,0-) 1,904.97 MeV
257Es 257.09598(44)# 7.7(2) d 7/2+# 1,913.04 MeV
258Es 258.09952(32)# 3# min 1,921.11 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. 4

Abundancia

Compuestos

Información de seguridad


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

Para más información

Enlaces externos:

Fuentes

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:10.
(2) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(5) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(7) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).