"Hahnium" redirects here. Not to be confused with Hafnium.
For the node.js release labeled "Dubnium", see node.js § Releases.
Chemical element, symbol Db and atomic number 105
Dubnium, 105Db
Dubnium
Pronunciation
/ˈduːbniəm/[1] (DOOB-nee-əm)
/ˈdʌbniəm/[2] (DUB-nee-əm)
Mass number
[268]
Dubnium in the periodic table
Hydrogen
Helium
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
Sodium
Magnesium
Aluminium
Silicon
Phosphorus
Sulfur
Chlorine
Argon
Potassium
Calcium
Scandium
Titanium
Vanadium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
Bromine
Krypton
Rubidium
Strontium
Yttrium
Zirconium
Niobium
Molybdenum
Technetium
Ruthenium
Rhodium
Palladium
Silver
Cadmium
Indium
Tin
Antimony
Tellurium
Iodine
Xenon
Caesium
Barium
Lanthanum
Cerium
Praseodymium
Neodymium
Promethium
Samarium
Europium
Gadolinium
Terbium
Dysprosium
Holmium
Erbium
Thulium
Ytterbium
Lutetium
Hafnium
Tantalum
Tungsten
Rhenium
Osmium
Iridium
Platinum
Gold
Mercury (element)
Thallium
Lead
Bismuth
Polonium
Astatine
Radon
Francium
Radium
Actinium
Thorium
Protactinium
Uranium
Neptunium
Plutonium
Americium
Curium
Berkelium
Californium
Einsteinium
Fermium
Mendelevium
Nobelium
Lawrencium
Rutherfordium
Dubnium
Seaborgium
Bohrium
Hassium
Meitnerium
Darmstadtium
Roentgenium
Copernicium
Nihonium
Flerovium
Moscovium
Livermorium
Tennessine
Oganesson
Ta ↑ Db ↓ (Upe)
rutherfordium ← dubnium → seaborgium
Atomic number (Z)
105
Group
group 5
Period
period 7
Block
d-block
Electron configuration
[Rn] 5f14 6d3 7s2[3]
Electrons per shell
2, 8, 18, 32, 32, 11, 2
Physical properties
Phase at STP
solid (predicted)[4]
Density (near r.t.)
21.6 g/cm3(predicted)[5][6]
Atomic properties
Oxidation states
(+3), (+4), +5[3][7] (parenthesized: prediction)
Ionization energies
1st: 665 kJ/mol
2nd: 1547 kJ/mol
3rd: 2378 kJ/mol
(more) (all but first estimated)[3]
Atomic radius
empirical: 139 pm (estimated)[3]
Covalent radius
149 pm (estimated)[8]
Other properties
Natural occurrence
synthetic
Crystal structure
body-centered cubic (bcc) (predicted)[4]
CAS Number
53850-35-4
History
Naming
after Dubna, Moscow Oblast, Russia, site of Joint Institute for Nuclear Research
Discovery
independently by the Lawrence Berkeley Laboratory and the Joint Institute for Nuclear Research (1970)
Isotopes of dubnium
v
e
Main isotopes[9]
Decay
abundance
half-life (t1/2)
mode
product
262Db
synth
34 s[10][11]
α67%
258Lr
SF33%
–
263Db
synth
27 s[11]
SF56%
–
α41%
259Lr
ε3%
263mRf
266Db
synth
11 min[12]
SF
–
ε
266Rf
267Db
synth
1.4 h[12]
SF
–
268Db
synth
16 h[13]
SF
–
ε
268Rf
α[13]
264Lr
270Db
synth
1 h[14]
SF17%
–
α83%
266Lr
Category: Dubnium
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Dubnium is a synthetic chemical element; it has symbol Db and atomic number 105. It is highly radioactive: the most stable known isotope, dubnium-268, has a half-life of about 16 hours. This greatly limits extended research on the element.
Dubnium does not occur naturally on Earth and is produced artificially. The Soviet Joint Institute for Nuclear Research (JINR) claimed the first discovery of the element in 1968, followed by the American Lawrence Berkeley Laboratory in 1970. Both teams proposed their names for the new element and used them without formal approval. The long-standing dispute was resolved in 1993 by an official investigation of the discovery claims by the Transfermium Working Group, formed by the International Union of Pure and Applied Chemistry and the International Union of Pure and Applied Physics, resulting in credit for the discovery being officially shared between both teams. The element was formally named dubnium in 1997 after the town of Dubna, the site of the JINR.
Theoretical research establishes dubnium as a member of group 5 in the 6d series of transition metals, placing it under vanadium, niobium, and tantalum. Dubnium should share most properties, such as its valence electron configuration and having a dominant +5 oxidation state, with the other group 5 elements, with a few anomalies due to relativistic effects. A limited investigation of dubnium chemistry has confirmed this.
^"dubnium". Merriam-Webster.com Dictionary. Retrieved March 24, 2018.
^"dubnium". Lexico UK English Dictionary. Oxford University Press. Archived from the original on December 18, 2019.
^ abcdHoffman, D. C.; Lee, D. M.; Pershina, V. (2006). "Transactinides and the future elements". In Morss, L.R.; Edelstein, N. M.; Fuger, Jean (eds.). The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Springer Science+Business Media. pp. 1652–1752. ISBN 978-1-4020-3555-5.
^ abÖstlin, A.; Vitos, L. (2011). "First-principles calculation of the structural stability of 6d transition metals". Physical Review B. 84 (11). Bibcode:2011PhRvB..84k3104O. doi:10.1103/PhysRevB.84.113104.
^Gyanchandani, Jyoti; Sikka, S. K. (May 10, 2011). "Physical properties of the 6 d -series elements from density functional theory: Close similarity to lighter transition metals". Physical Review B. 83 (17): 172101. doi:10.1103/PhysRevB.83.172101.
^Kratz; Lieser (2013). Nuclear and Radiochemistry: Fundamentals and Applications (3rd ed.). p. 631.
^Fricke, Burkhard (1975). "Superheavy elements: a prediction of their chemical and physical properties". Recent Impact of Physics on Inorganic Chemistry. Structure and Bonding. 21: 89–144. doi:10.1007/BFb0116498. ISBN 978-3-540-07109-9. Retrieved October 4, 2013.
^"Dubnium". Royal Chemical Society. Retrieved October 9, 2017.
^Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
^Münzenberg, G.; Gupta, M. (2011). "Production and Identification of Transactinide Elements". Handbook of Nuclear Chemistry. Springer. p. 877. doi:10.1007/978-1-4419-0720-2_19.
^ abSix New Isotopes of the Superheavy Elements Discovered. Berkeley Lab. News center. October 26, 2010
^ abOganessian, Yu. Ts.; Utyonkov, V. K.; Kovrizhnykh, N. D.; et al. (2022). "New isotope 286Mc produced in the 243Am+48Ca reaction". Physical Review C. 106 (064306). doi:10.1103/PhysRevC.106.064306.
^ abOganessian, Yu. Ts.; Utyonkov, V. K.; Kovrizhnykh, N. D.; et al. (September 29, 2022). "First experiment at the Super Heavy Element Factory: High cross section of 288Mc in the243Am+48Ca reaction and identification of the new isotope 264Lr". Physical Review C. 106 (3): L031301. doi:10.1103/PhysRevC.106.L031301. S2CID 252628992.
^Khuyagbaatar, J.; Yakushev, A.; Düllmann, Ch. E.; et al. (2014). "48Ca+249Bk Fusion Reaction Leading to Element Z=117: Long-Lived α-Decaying 270Db and Discovery of 266Lr". Physical Review Letters. 112 (17): 172501. Bibcode:2014PhRvL.112q2501K. doi:10.1103/PhysRevLett.112.172501. hdl:1885/148814. PMID 24836239. S2CID 5949620.
Dubnium is a synthetic chemical element; it has symbol Db and atomic number 105. It is highly radioactive: the most stable known isotope, dubnium-268...
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39th IUPAC General Assembly in Geneva, Switzerland. Element 105 was named dubnium (Db), after Dubna in Russia, the location of the JINR; the American suggestions...
(Ha) in honor of Otto Hahn. IUPAC recommended that element 105 be named dubnium, after Dubna. The element was discovered almost simultaneously by two laboratories...
from its daughter dubnium-257. Later, the dubnium isotope was corrected to dubnium-258, which indeed has a five-second half-life (dubnium-257 has a one-second...
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the 6d and 7p series in the periodic table. Except for rutherfordium and dubnium (and lawrencium if it is included), even the longest-lasting isotopes of...
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