introduction
Groupe: 5 or V B
Poids atomique: 262
Période: 7
Numero CAS: 53850-35-4
Classification
Pas d'isotopes stables
Solide
Liquide
Gaz
Solide (prédit)
La description • Usages / Fonction
In 1967 G. N. Flerov reported that a Soviet team working at the Joint Institute for Nuclear Research at Dubna may have produced a few atoms of 260105 and 261105 by bombarding 243Am with 22Ne. Their evidence was based on time-coincidence measurements of alpha energies. More recently, it was reported that early in 1970 Dubna scientists synthesized Element 105 and that by the end of April 1970 “had investigated all the types of decay of the new element and had determined its chemical properties.” The Soviet group proposed the name joliotium for Element 105. In late April 1970, it was announced that Ghiorso, Nurmia, Harris, K. A. Y. Eskola, and P. L. Eskola, working at the University of California at Berkeley, had positively identified Element 105. The discovery was made by bombarding a target of 249Cf with a beam of 84 MeV nitrogen nuclei in the Heavy Ion Linear Accelerator (HILAC). When a 15N nuclear is absorbed by a 249Cf nucleus, four neutrons are emitted and a new atom of 260105 with a halflife of 1.6 s is formed. While the first atoms of Element 105 are said to have been detected conclusively on March 5, 1970, there is evidence that Element 105 had been formed in Berkeley experiments a year earlier by the method described. Ghiorso and his associates have attempted to confirm Soviet findings by more sophisticated methods without success. In October 1971, it was announced that two new isotopes of Element 105 were synthesized with the heavy ion linear accelerator by A. Ghiorso and co-workers at Berkeley. Element 261105 was produced both by bombarding 250Cf with 15N and by bombarding 249Bk with 16O. The isotope emits 8.93-MeV alpha particles and decays to 257Lr with a half-life of about 1.8 s. Element 262105 was produced by bombarding 249Bk with 18O. It emits 8.45 MeV alpha particles and decays to 258Lr with a half-life of about 40 s. Eight isotopes of Element 105 are now recognized. In 1997, the International Union of Pure and Applied Chemistry adopted the name dubnium for Element 105. 1
Propriétés physiques
Densité: g/cm3
Configuration de l'électron: [Rn] 7s2 5f14 6d3
n = 6
* - at 1 atm
Configuration de l'électron
Bloque: d
Plus haut niveau d'énergie occupés: 7
Électrons de valence:
Nombres quantiques:
ℓ = 2
mℓ = 0
ms = +½
Bonding
isotopes
Nuclide
Masse 2
Demi vie 2
Spin nucléaire 2
Énergie de liaison
255Db
255.10740(45)#
1.7(5) s [1.6(+6-4) s]
1,882.89 MeV
256Db
256.10813(31)#
1.9(4) s [1.6(+5-3) s]
1,890.96 MeV
257Db
257.10772(24)#
1.53(17) s [1.50(+19-15) s]
(9/2+)
1,899.03 MeV
258Db
258.10923(37)#
4.5(6) s
1,907.10 MeV
259Db
259.10961(23)#
0.51(16) s
1,915.17 MeV
260Db
260.11130(25)#
1.52(13) s
1,913.93 MeV
261Db
261.11206(25)#
1.8(4) s
1,922.00 MeV
262Db
262.11408(20)#
35(5) s
1,930.07 MeV
263Db
263.11499(18)#
29(9) s [27(+10-7) s]
1,938.14 MeV
264Db
264.11740(25)#
3# min
1,946.21 MeV
265Db
265.1186(3)#
15# min
1,954.29 MeV
266Db
266.12103(39)#
20# min
1,953.04 MeV
267Db
267.12238(50)#
73(+350-33) min
1,961.11 MeV
268Db
268.12545(57)#
32(+11-7) h
1,969.18 MeV
269Db
269.12746(83)#
3# h
1,977.26 MeV
270Db
270.13071(77)#
1# h
1,976.01 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. 2
Abondance
Information de sécurité
Fiche signalétique - ACI Alloys, Inc.
Pour plus d'informations
Liens externes:
American Elements
Chemical & Engineering News
Chemical Elements
ChemGlobe
Chemicool
Environmental Chemistry
Sources
(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; pp 6:193, 12:219-220.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(5) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).