Bohrium
Atomic Data
| Atomic Number | 107 |
| Symbol | Bh |
| Atomic Weight | 270 u |
| Density (STP) | N/A |
| Melting Point | N/A °C (None K) |
| Boiling Point | N/A °C (None K) |
| Electronegativity | : |
| Electron Config. | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d5 7s2 |
| Oxidation States | +7 |
| Phase at STP | Solid |
| Category | Transition Metal |
| Period / Group | 7 / 7 |
| CAS Number | 54037-14-8 |
Electron Configuration
[Rn] 5f14 6d5 7s2
| Shell | n | Subshell | Electrons | Cumulative |
|---|---|---|---|---|
| K | 1 | 1s | 2 | 2 |
| L | 2 | 2s | 2 | 4 |
| L | 2 | 2p | 6 | 10 |
| M | 3 | 3s | 2 | 12 |
| M | 3 | 3p | 6 | 18 |
| M | 3 | 3d | 10 | 28 |
| N | 4 | 4s | 2 | 30 |
| N | 4 | 4p | 6 | 36 |
| N | 4 | 4d | 10 | 46 |
| N | 4 | 4f | 14 | 60 |
| O | 5 | 5s | 2 | 62 |
| O | 5 | 5p | 6 | 68 |
| O | 5 | 5d | 10 | 78 |
| O | 5 | 5f | 14 | 92 |
| P | 6 | 6s | 2 | 94 |
| P | 6 | 6p | 6 | 100 |
| P | 6 | 6d | 5 | 105 |
| Q | 7 | 7s | 2 | 107 |
| Total | 107 | 107 | ||
Isotopes of Bohrium
Bohrium has two naturally occurring stable isotopes. The most abundant is ²⁷⁰Bh, comprising None% of all naturally occurring Bohrium.
| Isotope | Symbol | Protons | Neutrons | Abundance | Stability |
|---|---|---|---|---|---|
| Bohrium-270 | ²⁷⁰Bh | 107 | 163 | trace | Stable |
| Bohrium-272 | ²⁷²Bh | 107 | 165 | trace | Stable |
Abundance & Occurrence
Bohrium is present in Earth's crust at approximately trace amounts by mass and at approximately trace amounts by mass throughout the universe.
Earth's Crust (ppm by mass)
Universe (ppm by mass)
Discovery & History
Read more about the discovery of the periodic table of elements →
Safety & Handling
- Alpha radiation and short half-life: Bohrium isotopes are short-lived alpha emitters; Bh-270 (t½ = 61 s) is the longest-lived, making chemical experiments extremely challenging and hazardous to attempt in real-time.
- Atom-at-a-time scale: Only a few hundred atoms of bohrium have ever been synthesised; there is no practical bulk radiological or chemical hazard from the element itself.
- Accelerator radiation environment: The primary occupational hazard is the radiation environment of the heavy ion accelerator required to produce bohrium, not the element itself.
- Regulatory controls: All bohrium experiments are conducted at licensed nuclear research facilities with full radiation protection and safety programmes.
Bohrium in the Real World
Real-World Uses
- Superheavy element research: Bohrium (Bh-270, Bh-274) is produced at heavy-ion accelerators and studied to confirm its Group 7 chemistry alongside manganese, technetium, and rhenium; gas-phase chromatography experiments measure the volatility of BhO₃Cl relative to lighter homologues.
- Nuclear decay chain mapping: Bohrium isotopes serve as intermediate steps in the alpha-decay chains of heavier superheavy elements (113–115), providing crucial data for establishing the synthesis and identification of those heavier species.
- No commercial applications: Bohrium is produced in quantities of tens to hundreds of atoms; the most stable isotope (Bh-270) has a half-life of about 61 seconds, making any practical application impossible.
Downloadable Resources
Free periodic table reference sheets for classrooms, study sessions, and laboratory use.
Frequently Asked Questions
Has bohrium ever been used for anything?
No. Bohrium has no known practical uses. Its most stable isotope (Bh-274) has a half-life of about 54 seconds. It is produced a few atoms at a time in particle accelerators and studied purely for fundamental research into superheavy element chemistry and nuclear structure.
How many atoms of bohrium have been made?
Only a small number of bohrium atoms have ever been produced: typically a few atoms per hour in accelerator experiments under optimal conditions. All bohrium chemistry experiments have involved just a handful of atoms at a time, studied individually using rapid online chemical separation before the atoms decay.
Is bohrium radioactive?
Yes, all isotopes of bohrium are radioactive. The longest-lived is Bh-274, with a half-life of about 54 seconds. Most other isotopes decay in milliseconds to seconds. Bohrium is produced and detected at the single-atom level at particle accelerator facilities.
How did bohrium get its name?
Bohrium was named after Niels Bohr, the Danish physicist who developed the foundational model of atomic structure (particularly the quantised electron shell model) and made seminal contributions to quantum mechanics. The element was discovered at GSI Helmholtz Centre in Darmstadt, Germany, in 1981. The name was approved by IUPAC in 1997, resolving a long dispute during which the element was provisionally called unnilseptium.