EINSTEINIUM

introduzione

Numero atomico: 99
Gruppo: Nessuna
Peso atomico: 252
Periodo: 7
Numero CAS: 7429-92-7

Classificazione

Metallo
Metalloide
simile a metallo
metallo alcalino
Alkali terroso
Metallo di transizione
calcogeno
alogena
Gas nobile
Lanthanoid
Actinoid
Terre rare
Platinum Metal Group
transuranici
Non ci sono isotopi stabili
Solido
Liquido
Gas
Solido (previsto)

Descrizione • Usi / Funzione

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

Proprietà fisiche

Punto di fusione:2*  860 °C = 1133.15 K = 1580 °F
Punto di ebollizione:2
sublimazione Point:2 
Triple Point:2 
Punto critico:2 
Densità:   g/cm3

* - at 1 atm

configurazione elettronica

configurazione elettronica:  *[Rn] 7s2 5f11
Bloccare: f
Più alto livello di energia Occupato: 7
Elettroni di valenza: 2

numeri quantici:

n = 5
ℓ = 3
m = 0
ms = -½

bonding

potenziale di ionizzazione   eV 3  kJ/mol  
potenziale di ionizzazione   eV 3  kJ/mol  
potenziale di ionizzazione   eV 3  kJ/mol  
1 6.42    619.4

isotopi

nuclide Massa 4 Metà vita 4 spin nucleare 4 Energia di legame
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
I valori assegnati # non sono puramente derivati ​​da dati sperimentali, ma almeno parzialmente da tendenze sistematiche. Gira con argomenti di assegnazione deboli sono racchiusi tra parentesi. 4

Abbondanza

Composti

Informazioni sulla sicurezza


Scheda di sicurezza - ACI Alloys, Inc.

Per maggiori informazioni

Link esterno:

fonti

(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).