Bohrium Facts - Element 107 or Bh

Bohrium History, Properties, Uses, and Sources

Bohrium is a radioactive metallic transition element.
Bohrium is a radioactive metallic transition element. Science Picture Co / Getty Images

Bohrium is a transition metal with atomic number 107 and element symbol Bh. This man-made element is radioactive and toxic. Here is a collection of interesting bohrium element facts, including its properties, sources, history, and uses.

  • Bohrium is a synthetic element. To date, it has only been produced in a lab and has not been found in nature. It is expected to be a dense solid metal at room temperature.
  • Credit for the discovery and isolation of element 107 is given to Peter Armbruster, Gottfried Münzenberg, and their team (German) at the GSI Helmholtz Centre or Heavy Ion Research in Darmstadt. In 1981, they bombarded a bismuth-209 target with chromium-54 nuclei to obtain 5 atoms of bohrium-262. However, the first production of the element may have been in 1976 when Yuri Oganessian and his team bombarded bismuth-209 and lead-208 targets with chromium-54 and manganese-58 nuclei (respectively). The team believed it obtained bohrium-261 and dubnium-258, which decays into bohrium-262. However, the IUPAC/IUPAP Transfermium Working Group (TWG) did not feel there was conclusive evidence of bohrium production.
  • The German group proposed the element name nielsbohrium with element symbol Ns to honor physicist Niel Bohr. The Russian scientists at the Joint Institute for Nuclear Research in Dubna, Russia suggested the element name be given to element 105. In the end, 105 was named dubnium, so the Russian team agreed to the German proposed name for element 107. However, the IUPAC committee recommended the name be revised to bohrium because there were no other elements with a complete name in them. The discoverers did not embrace this proposal, believing the name bohrium was too close to the element name boron. Even so, the IUPAC officially recognized bohrium as the name for element 107 in 1997.
  • Experimental data indicates bohrium shares chemical properties with its homologue element rhenium, which is located directly above it on the periodic table. Its most stable oxidation state is expected to be +7.
  • All isotopes of bohrium are unstable and radioactive. Known isotopes range in atomic mass from 260-262, 264-267, 270-272, and 274. At least one metastable state is known. The isotopes decay via alpha decay. Other isotopes may be susceptible to spontaneous fission. The most stable isotope is bohium-270, which has a half-life of 61 seconds.
  • At present, the only uses for bohrium are for experiments to learn more about its properties and to use it to synthesize isotopes of other elements.
  • Bohrium serves no biological function. Because it is a heavy metal and decays to produce alpha particles, it is extremely toxic.

Bohrium Properties

Element Name: Bohrium

Element Symbol: Bh

Atomic Number: 107

Atomic Weight: [270] based on longest-lived isotope

Electron Configuration: [Rn] 5f14 6d5 7s2 (2, 8, 18, 32, 32, 13, 2)

Discovery: Gesellschaft für Schwerionenforschung, Germany (1981)

Element Group: transition metal, group 7, d-block element

Element Period: period 7

Phase: Bohrium is predicted to be a solid metal at room temperature.

Density: 37.1 g/cm3 (predicted near room temperature)

Oxidation States7, (5), (4), (3) with states in parentheses predicted ones

Ionization Energy: 1st: 742.9 kJ/mol, 2nd: 1688.5 kJ/mol (estimate), 3rd: 2566.5 kJ/mol (estimate)

Atomic Radius: 128 picometers (empirical data)

Crystal Structure: predicted to be hexagonal close-packed (hcp)

Selected References:

Oganessian, Yuri Ts.; Abdullin, F. Sh.; Bailey, P. D.; et al. (2010-04-09). "Synthesis of a New Element with Atomic Number Z=117". Physical Review Letters. American Physical Society.

 104 (142502).

Ghiorso, A.; Seaborg, G.T.; Organessian, Yu. Ts.; Zvara, I.; Armbruster, P.; Hessberger, F.P.; Hofmann, S.; Leino, M.; Munzenberg, G.; Reisdorf, W.; Schmidt, K.-H. (1993). "Responses on 'Discovery of the transfermium elements' by Lawrence Berkeley Laboratory, California; Joint Institute for Nuclear Research, Dubna; and Gesellschaft fur Schwerionenforschung, Darmstadt followed by reply to responses by the Transfermium Working Group". Pure and Applied Chemistry65 (8): 1815–1824.

Hoffman, Darleane C.; Lee, Diana M.; Pershina, Valeria (2006). "Transactinides and the future elements". In Morss; Edelstein, Norman M.; Fuger, Jean. The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands: Springer Science+Business Media.

Fricke, Burkhard (1975). "Superheavy elements: a prediction of their chemical and physical properties".

 Recent Impact of Physics on Inorganic Chemistry21: 89–144.