Berkelium

  • berkelium, 97bk
    berkelium metal.jpg
    berkelium
    pronunciation
    • m/
      (kel-ee-əm)
    • m/
      (bur-klee-əm)
    appearancesilvery
    mass number[247]
    berkelium 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
    tb

    bk

    (upu)
    curiumberkeliumcalifornium
    atomic number (z)97
    groupgroup n/a
    periodperiod 7
    blockf-block
    element category  actinide
    electron configuration[rn] 5f9 7s2
    electrons per shell2, 8, 18, 32, 27, 8, 2
    physical properties
    phase at stpsolid
    melting pointbeta: 1259 k ​(986 °c, ​1807 °f)
    boiling pointbeta: 2900 k ​(2627 °c, ​4760 °f)
    density (near r.t.)alpha: 14.78 g/cm3
    beta: 13.25 g/cm3
    heat of fusion7.92 kj/mol (calculated)
    atomic properties
    oxidation states+2, +3, +4, +5[1]
    electronegativitypauling scale: 1.3
    ionization energies
    • 1st: 601 kj/mol
    atomic radiusempirical: 170 pm
    color lines in a spectral range
    spectral lines of berkelium
    other properties
    natural occurrencesynthetic
    crystal structuredouble hexagonal close-packed (dhcp)
    double hexagonal close packed crystal structure for berkelium
    thermal conductivity10 w/(m·k)
    magnetic orderingparamagnetic
    cas number7440-40-6
    history
    namingafter berkeley, california, where it was discovered
    discoverylawrence berkeley national laboratory (1949)
    main isotopes of berkelium
    iso­tope abun­dance half-life (t1/2) decay mode pro­duct
    245bk syn 4.94 d ε 245cm
    α 241am
    246bk syn 1.8 d α 242am
    ε 246cm
    247bk syn 1380 y α 243am
    248bk syn >300 y[2] α 244am
    249bk syn 330 d α 245am
    sf
    β 249cf
    category category: berkelium
    | references

    berkelium is a transuranic radioactive chemical element with the symbol bk and atomic number 97. it is a member of the actinide and transuranium element series. it is named after the city of berkeley, california, the location of the lawrence berkeley national laboratory (then the university of california radiation laboratory) where it was discovered in december 1949. berkelium was the fifth transuranium element discovered after neptunium, plutonium, curium and americium.

    the major isotope of berkelium, 249bk, is synthesized in minute quantities in dedicated high-flux nuclear reactors, mainly at the oak ridge national laboratory in tennessee, usa, and at the research institute of atomic reactors in dimitrovgrad, russia. the production of the second-most important isotope 247bk involves the irradiation of the rare isotope 244cm with high-energy alpha particles.

    just over one gram of berkelium has been produced in the united states since 1967. there is no practical application of berkelium outside scientific research which is mostly directed at the synthesis of heavier transuranic elements and transactinides. a 22 milligram batch of berkelium-249 was prepared during a 250-day irradiation period and then purified for a further 90 days at oak ridge in 2009. this sample was used to synthesize the new element tennessine for the first time in 2009 at the joint institute for nuclear research, russia, after it was bombarded with calcium-48 ions for 150 days. this was the culmination of the russia–us collaboration on the synthesis of the heaviest elements on the periodic table.

    berkelium is a soft, silvery-white, radioactive metal. the berkelium-249 isotope emits low-energy electrons and thus is relatively safe to handle. it decays with a half-life of 330 days to californium-249, which is a strong emitter of ionizing alpha particles. this gradual transformation is an important consideration when studying the properties of elemental berkelium and its chemical compounds, since the formation of californium brings not only chemical contamination, but also free-radical effects and self-heating from the emitted alpha particles.

  • characteristics
  • history
  • synthesis and extraction
  • compounds
  • applications
  • nuclear fuel cycle
  • health issues
  • references
  • bibliography
  • external links

Berkelium, 97Bk
Berkelium metal.jpg
Berkelium
Pronunciation
Appearancesilvery
Mass number[247]
Berkelium 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
Tb

Bk

(Upu)
curiumberkeliumcalifornium
Atomic number (Z)97
Groupgroup n/a
Periodperiod 7
Blockf-block
Element category  Actinide
Electron configuration[Rn] 5f9 7s2
Electrons per shell2, 8, 18, 32, 27, 8, 2
Physical properties
Phase at STPsolid
Melting pointbeta: 1259 K ​(986 °C, ​1807 °F)
Boiling pointbeta: 2900 K ​(2627 °C, ​4760 °F)
Density (near r.t.)alpha: 14.78 g/cm3
beta: 13.25 g/cm3
Heat of fusion7.92 kJ/mol (calculated)
Atomic properties
Oxidation states+2, +3, +4, +5[1]
ElectronegativityPauling scale: 1.3
Ionization energies
  • 1st: 601 kJ/mol
Atomic radiusempirical: 170 pm
Color lines in a spectral range
Spectral lines of berkelium
Other properties
Natural occurrencesynthetic
Crystal structuredouble hexagonal close-packed (dhcp)
Double hexagonal close packed crystal structure for berkelium
Thermal conductivity10 W/(m·K)
Magnetic orderingparamagnetic
CAS Number7440-40-6
History
Namingafter Berkeley, California, where it was discovered
DiscoveryLawrence Berkeley National Laboratory (1949)
Main isotopes of berkelium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
245Bk syn 4.94 d ε 245Cm
α 241Am
246Bk syn 1.8 d α 242Am
ε 246Cm
247Bk syn 1380 y α 243Am
248Bk syn >300 y[2] α 244Am
249Bk syn 330 d α 245Am
SF
β 249Cf
Category Category: Berkelium
| references

Berkelium is a transuranic radioactive chemical element with the symbol Bk and atomic number 97. It is a member of the actinide and transuranium element series. It is named after the city of Berkeley, California, the location of the Lawrence Berkeley National Laboratory (then the University of California Radiation Laboratory) where it was discovered in December 1949. Berkelium was the fifth transuranium element discovered after neptunium, plutonium, curium and americium.

The major isotope of berkelium, 249Bk, is synthesized in minute quantities in dedicated high-flux nuclear reactors, mainly at the Oak Ridge National Laboratory in Tennessee, USA, and at the Research Institute of Atomic Reactors in Dimitrovgrad, Russia. The production of the second-most important isotope 247Bk involves the irradiation of the rare isotope 244Cm with high-energy alpha particles.

Just over one gram of berkelium has been produced in the United States since 1967. There is no practical application of berkelium outside scientific research which is mostly directed at the synthesis of heavier transuranic elements and transactinides. A 22 milligram batch of berkelium-249 was prepared during a 250-day irradiation period and then purified for a further 90 days at Oak Ridge in 2009. This sample was used to synthesize the new element tennessine for the first time in 2009 at the Joint Institute for Nuclear Research, Russia, after it was bombarded with calcium-48 ions for 150 days. This was the culmination of the Russia–US collaboration on the synthesis of the heaviest elements on the periodic table.

Berkelium is a soft, silvery-white, radioactive metal. The berkelium-249 isotope emits low-energy electrons and thus is relatively safe to handle. It decays with a half-life of 330 days to californium-249, which is a strong emitter of ionizing alpha particles. This gradual transformation is an important consideration when studying the properties of elemental berkelium and its chemical compounds, since the formation of californium brings not only chemical contamination, but also free-radical effects and self-heating from the emitted alpha particles.