LAWRENCIUM

introduction

Numéro atomique: 103
Groupe: Aucun
Poids atomique: 262
Période: 7
Numero CAS: 22537-19-5

Classification

chalcogènes
Halogène
Gaz rare
lanthanides
actinides
Rare Earth Element
Groupe Platine Métal
Transuranium
Pas d'isotopes stables
Solide
Liquide
Gaz
Solide (prédit)

La description • Usages / Fonction

This member of the 5f transition elements (actinide series) was discovered in March 1961 by A. Ghiorso, T. Sikkeland, A. E. Larsh, and R. M. Latimer.A 3 microgram californium target, consisting of a mixture of isotopes of mass number 249, 250, 251, and 252, was bombarded with either 10B or 11B. The electrically charged transmutation nuclei recoiled with an atmosphere of helium and were collected on a thin copper conveyor tape which was then moved to place collected atoms in front of a series of solid-state detectors. The isotope of element 103 produced in this way decayed by emitting an 8.6-MeV alpha particle with a halflife of 8 s. In 1967, Flerov and associates of the Dubna Laboratory reported their inability to detect an alpha emitter with a half-life of 8 s which was assigned by the Berkeley group to Element 103-257. This assignment has been changed to lawrencium-258 or lawrencium-259. In 1965, the Dubna workers found a longer-lived lawrencium isotope, lawrencium-256, with a half-life of 35 s. In 1968, Ghiorso and associates at Berkeley were able to use a few atoms of this isotope to study the oxidation behavior of lawrencium. Using solvent extraction techniques and working very rapidly, they extracted lawrencium ions from a buffered aqueous solution into an organic solvent, completing each extraction in about 30 s. It was found that lawrencium behaves differently from dipositive nobelium and more like the tripositive elements earlier in the actinide series. Ten isotopes of lawrencium are now recognized. 1

Propriétés physiques

Point de fusion:2*  1627 °C = 1900.15 K = 2960.6 °F
Point d'ébullition:2
sublimation point:2 
Triple point:2 
Point critique:2 
Densité:   g/cm3

* - at 1 atm

Configuration de l'électron

Configuration de l'électron:  *[Rn] 7s2 5f14 6d1
Bloque: f
Plus haut niveau d'énergie occupés: 7
Électrons de valence: 2

Nombres quantiques:

n = 6
ℓ = 2
m = -2
ms = +½

Bonding

ionisation potentiel   eV 3  kJ/mol  
ionisation potentiel   eV 3  kJ/mol  
ionisation potentiel   eV 3  kJ/mol  
1 4.9    472.8

isotopes

Nuclide Masse 4 Demi vie 4 Spin nucléaire 4 Énergie de liaison
251Lr 251.09436(32)# 150# μs 1,861.48 MeV
252Lr 252.09537(27)# 390(90) ms [0.36(+11-7) s] 1,869.55 MeV
253Lr 253.09521(24)# 580(70) ms [0.57(+7-6) s] (7/2-) 1,877.62 MeV
254Lr 254.09645(36)# 13(3) s 1,885.70 MeV
255Lr 255.09668(22)# 22(4) s 7/2-# 1,893.77 MeV
256Lr 256.09863(24)# 27(3) s 1,901.84 MeV
257Lr 257.09956(22)# 646(25) ms 9/2+# 1,909.91 MeV
258Lr 258.10181(11)# 4.1(3) s 1,908.67 MeV
259Lr 259.10290(8)# 6.2(3) s 9/2+# 1,916.74 MeV
260Lr 260.10550(12)# 2.7 min 1,924.81 MeV
261Lr 261.10688(22)# 44 min 1,932.88 MeV
262Lr 262.10963(22)# 216 min 1,940.95 MeV
263Lr 263.11129(39)# 5# h 1,939.71 MeV
264Lr 264.11404(47)# 10# h 1,947.78 MeV
265Lr 265.11584(77)# 10# h 1,955.85 MeV
266Lr 266.11931(70)# 1# h 1,963.92 MeV
Les valeurs marquées # ne sont pas purement dérivées des données expérimentales, mais au moins en partie des tendances systématiques. Spins avec de faibles arguments d'affectation sont entre parenthèses. 4

Abondance

Information de sécurité


Fiche signalétique - ACI Alloys, Inc.

Pour plus d'informations

Liens externes:

Sources

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:17.
(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).