Dubnium

  • dubnium, 105db
    dubnium
    pronunciation
    • m/[1]
      (doob-nee-əm)
    • m/[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)
    rutherfordiumdubniumseaborgium
    atomic number (z)105
    groupgroup 5
    periodperiod 7
    blockd-block
    element category  transition metal
    electron configuration[rn] 5f14 6d3 7s2[3]
    electrons per shell2, 8, 18, 32, 32, 11, 2
    physical properties
    phase at stpsolid (predicted)[4]
    density (near r.t.)29.3 g/cm3 (predicted)[3][5]
    atomic properties
    oxidation states(+3), (+4), +5[3][5] (parenthesized: prediction)
    ionization energies
    • 1st: 665 kj/mol
    • 2nd: 1547 kj/mol
    • 3rd: 2378 kj/mol
    • (more) (all but first estimated)[3]
    atomic radiusempirical: 139 pm (estimated)[3]
    covalent radius149 pm (estimated)[6]
    other properties
    natural occurrencesynthetic
    crystal structurebody-centered cubic (bcc) (predicted)[4]
    body-centered cubic crystal structure for dubnium
    cas number53850-35-4
    history
    namingafter dubna, moscow oblast, russia, site of joint institute for nuclear research
    discoveryindependently by the lawrence berkeley laboratory and the joint institute for nuclear research (1970)
    main isotopes of dubnium
    iso­tope abun­dance half-life (t1/2) decay mode pro­duct
    262db syn 34 s[7][8] 67% α 258lr
    33% sf
    263db syn 27 s[8] 56% sf
    41% α 259lr
    3% ε 263mrf
    266db syn 20 min[8] sf
    ε? 266rf
    267db syn 1.2 h[8] sf
    ε? 267rf
    268db syn 28 h[8] sf
    ε? 268rf
    270db syn 15 h[9] 17% sf
    83% α 266lr
    ε? 270rf
    | references

    dubnium is a synthetic chemical element with the symbol db and atomic number 105. dubnium is highly radioactive: the most stable known isotope, dubnium-268, has a half-life of about 28 hours. this greatly limits the extent of research on dubnium.

    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. solution chemistry experiments have revealed that dubnium often behaves more like niobium rather than tantalum, breaking periodic trends.

  • discovery
  • isotopes
  • predicted properties
  • experimental chemistry
  • notes
  • references

Dubnium, 105Db
Dubnium
Pronunciation
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)
rutherfordiumdubniumseaborgium
Atomic number (Z)105
Groupgroup 5
Periodperiod 7
Blockd-block
Element category  Transition metal
Electron configuration[Rn] 5f14 6d3 7s2[3]
Electrons per shell2, 8, 18, 32, 32, 11, 2
Physical properties
Phase at STPsolid (predicted)[4]
Density (near r.t.)29.3 g/cm3 (predicted)[3][5]
Atomic properties
Oxidation states(+3), (+4), +5[3][5] (parenthesized: prediction)
Ionization energies
  • 1st: 665 kJ/mol
  • 2nd: 1547 kJ/mol
  • 3rd: 2378 kJ/mol
  • (more) (all but first estimated)[3]
Atomic radiusempirical: 139 pm (estimated)[3]
Covalent radius149 pm (estimated)[6]
Other properties
Natural occurrencesynthetic
Crystal structurebody-centered cubic (bcc) (predicted)[4]
Body-centered cubic crystal structure for dubnium
CAS Number53850-35-4
History
Namingafter Dubna, Moscow Oblast, Russia, site of Joint Institute for Nuclear Research
Discoveryindependently by the Lawrence Berkeley Laboratory and the Joint Institute for Nuclear Research (1970)
Main isotopes of dubnium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
262Db syn 34 s[7][8] 67% α 258Lr
33% SF
263Db syn 27 s[8] 56% SF
41% α 259Lr
3% ε 263mRf
266Db syn 20 min[8] SF
ε? 266Rf
267Db syn 1.2 h[8] SF
ε? 267Rf
268Db syn 28 h[8] SF
ε? 268Rf
270Db syn 15 h[9] 17% SF
83% α 266Lr
ε? 270Rf
| references

Dubnium is a synthetic chemical element with the symbol Db and atomic number 105. Dubnium is highly radioactive: the most stable known isotope, dubnium-268, has a half-life of about 28 hours. This greatly limits the extent of research on dubnium.

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. Solution chemistry experiments have revealed that dubnium often behaves more like niobium rather than tantalum, breaking periodic trends.