Bohrium (Bh)
“Named for Niels Bohr, master of the atom — its discovery at Darmstadt in 1981 rested on just a handful of atoms.”
How its electrons are arranged
Computed from the aufbau principle, with known real-world exceptions applied automatically.
Characteristics
- A synthetic Group 7 transition metal — the superheavy relative of technetium and rhenium — made only one atom at a time.
- Even its longest-lived isotope Bh-270 lasts only about a minute, so experimenters must work almost instantaneously.
- Gas-phase chemistry showed its oxychloride BhO₃Cl is volatile like rhenium’s ReO₃Cl — the family trend holds, just barely.
- Like everything beyond element 104, its electrons race at relativistic speeds, subtly reshaping its chemical bonds.
Bohrium has never been seen — only counted, atom by atom, through its decay flashes. It should be a heavy, silvery Group 7 transition metal beneath rhenium and technetium, with properties bent by the relativistic effects that grow extreme this far down the table.
Where you meet it
✦ Uses
- Verifying Period 7’s vertical trends: comparing volatile BhO₃Cl with ReO₃Cl tests how relativity presses on Group 7 chemistry.
- Decay-chain anchoring: bohrium’s known alpha energies serve as signposts when still-heavier elements are being identified.
- Pushing one-atom-at-a-time chemical methods to their limit — the faster, hotter separations pioneered for Bh guide later work.
◍ Everyday examples
- NCTB chemistry introduces Bohr’s shell model of the atom — the same physicist whose name element 107 carries into Period 7.
- The wall chart of Bohr’s atomic model hanging in your classroom quietly salutes element 107 as well.
History & name
In 1981 a team at the GSI heavy-ion research centre in Darmstadt, Germany, led by Peter Armbruster and Gottfried Münzenberg, bombarded bismuth-209 with chromium-54 ions from the UNILAC accelerator and traced the alpha-decay chain of Bh-262 back through known isotopes — the rigorous new method that made their discoveries stick. The discoverers proposed the name nielsbohrium; IUPAC trimmed it to bohrium in 1997, honouring the Danish physicist Niels Bohr.