Berkelium
Berkelium is a synthetic, intensely radioactive metal made atom by atom in particle accelerators. It has no use outside of research, but it has played a working role in that research — as the target material scientists bombard to synthesize even heavier elements.
- Group · Period
- — · 7
- At room temp
- solid
- Melts at
- 1323 K
- Density
- 14 g/cm³
- Discovered
- 1949
Uses
Berkelium has no commercial or industrial use — it exists only in laboratories, in quantities too small and too radioactive for anything beyond research. Its most notable practical role has been as a target material: berkelium-249 has been bombarded with ion beams in efforts to synthesize elements even further down the periodic table, including tennessine, element 117. Beyond that kind of use, berkelium is studied mainly to understand how actinide chemistry behaves at these extremes.
History
Berkelium was first produced in December 1949 by Stanley Thompson, Albert Ghiorso, and Glenn Seaborg at the University of California, Berkeley, who bombarded americium with alpha particles in a cyclotron. It was the fifth transuranium element discovered by the Berkeley team in less than a decade, and like several others in that run, it was named directly after the city and laboratory where it was made.
Fun facts
- Berkelium is named after Berkeley, California, home to the laboratory where it and many other elements on this list were first made.
- Berkelium-249 served as the target material in the experiments that first synthesized tennessine, element 117, decades after berkelium itself was discovered.
- Only milligram-scale quantities of berkelium have ever been produced worldwide, and each batch is extraordinarily expensive to make.
Frequently asked questions
Does berkelium have any practical use?
Not commercially. Its only real use is as a research tool: specific berkelium isotopes have been used as target material, bombarded with accelerated ions to attempt the synthesis of still heavier, even more short-lived elements.
Why is it named berkelium?
It's named directly after Berkeley, California, home to the University of California and Lawrence Berkeley National Laboratory, where it was discovered — following the same pattern used for californium, discovered by the same team shortly after.
How is something this rare and radioactive even studied?
With extreme difficulty. Researchers work with vanishingly small quantities, often far less than a milligram, using specialized remote-handling equipment and radiochemical techniques designed to extract meaningful data from just a few atoms at a time.
Compounds
1 notable compound containing Bk
- BkO2oxide
Berkelium dioxide
A dark brown solid with the fluorite structure common to tetravalent actinide oxides, and one of only a handful of berkelium compounds ever isolated and characterized. It has been produced and studied only in microgram amounts.
Isotopes
18 known isotopes
Swipe to see all columns →
| Isotope | Natural abundance | Half-life | Decay mode | Mass excess | Binding energy / nucleon | Decay width |
|---|---|---|---|---|---|---|
| Bk-247 | — | 1380 Y | Alpha decay (100%) | 65,489.52 keV | 7,498.94 keV | 1.05 × 10-26 eV |
| Bk-248 | — | 9 Y | Unknown | 68,131.05 keV | 7,490.6 keV | 1.61 × 10-24 eV |
| Bk-249 | — | 330 d | Beta-minus decay (99.99855%), Alpha decay (0.00145%), Spontaneous fission (4.7e-8%) | 69,846.33 keV | 7,486.04 keV | 1.60 × 10-23 eV |
Show all 18 isotopes
| Bk-233 | — | 21 s | Electron capture / beta-plus decay, Alpha decay | 52,771 keV | 7,519 keV | 2.17 × 10-17 eV |
| Bk-234 | — | 1.4E2 s | Alpha decay (80%), Electron capture (20%) | 53,395 keV | 7,519 keV | 3.26 × 10-18 eV |
| Bk-236 | — | 22 s | Electron capture / beta-plus decay (83%), Alpha decay (17%), SF+EC+B+ (4%) | 53,542 keV | 7,523 keV | 2.07 × 10-17 eV |
| Bk-238 | — | 144 s | Electron capture / beta-plus decay (100%), SF+EC+B+ (0.048%) | 54,216 keV | 7,525 keV | 3.17 × 10-18 eV |
| Bk-239 | — | — | Electron capture (99%), Spontaneous fission (1%), Alpha decay (1%) | 54,250 keV | 7,527 keV | — |
| Bk-240 | — | 4.8 m | ECSF (0.002%), Electron capture / beta-plus decay | 55,664 keV | 7,523 keV | 1.58 × 10-18 eV |
| Bk-241 | — | 4.6 m | Alpha decay, Electron capture / beta-plus decay | 55,981 keV | 7,524 keV | 1.65 × 10-18 eV |
| Bk-242 | — | 7.0 m | Electron capture / beta-plus decay (99.5%), Alpha decay (0.5%) | 57,752 keV | 7,519 keV | 1.09 × 10-18 eV |
| Bk-243 | — | 4.6 h | Electron capture / beta-plus decay (99.85%), Alpha decay (0.15%) | 58,689.63 keV | 7,517.5 keV | 2.76 × 10-20 eV |
| Bk-244 | — | 5.02 h | Electron capture (99.994%), Alpha decay (0.006%) | 60,713.83 keV | 7,511.48 keV | 2.52 × 10-20 eV |
| Bk-245 | — | 4.95 d | Electron capture (99.88%), Alpha decay (0.12%) | 61,813.78 keV | 7,509.27 keV | 1.07 × 10-21 eV |
| Bk-246 | — | 1.80 d | Electron capture / beta-plus decay (100%) | 63,966.91 keV | 7,502.8 keV | 2.93 × 10-21 eV |
| Bk-250 | — | 3.212 h | Beta-minus decay (100%) | 72,952.01 keV | 7,475.96 keV | 3.95 × 10-20 eV |
| Bk-251 | — | 55.6 m | Beta-minus decay (100%) | 75,227.98 keV | 7,469.26 keV | 1.37 × 10-19 eV |
| Bk-253 | — | 10 m | Unknown | 80,929 keV | 7,451 keV | 7.60 × 10-19 eV |