Einsteinium
Einsteinium is a synthetic, intensely radioactive metal with an unusual origin story — it wasn't made in a lab reactor at all, but discovered in the radioactive debris of the first hydrogen bomb test. It has no practical use and exists purely as a subject of nuclear research.
- Group · Period
- — · 7
- At room temp
- solid
- Melts at
- 1133 K
- Density
- Not yet available
- Discovered
- 1952
Uses
Einsteinium has no practical use outside of research. It’s produced in vanishingly small quantities, is intensely radioactive, and decays far too quickly to be useful for anything beyond studying the chemistry of the actinide series itself. Its main scientific contribution has been as a stepping stone: einsteinium was used as a target material in the experiments that went on to produce the next element, mendelevium.
History
Einsteinium was discovered in the radioactive debris left by Ivy Mike, the first full-scale hydrogen bomb test, detonated by the United States in the Pacific in November 1952. Scientists analyzing coral and debris from the test site found evidence of the new element, formed when the explosion’s intense burst of neutrons was absorbed by uranium faster than the resulting nuclei could decay away. Because the discovery was tied directly to a classified weapons test, it wasn’t announced publicly until 1955. It was named after Albert Einstein.
Fun facts
- Einsteinium was first identified in the radioactive fallout of Ivy Mike, the first hydrogen bomb test, detonated in the Pacific in November 1952.
- Its discovery was kept classified for military reasons and wasn't made public until 1955, three years after the element was actually found.
- It's named after Albert Einstein, and was announced to the public in the same year he died.
Frequently asked questions
Does einsteinium have any practical use?
No. It has no commercial or industrial application whatsoever. Its only role has been in fundamental nuclear and actinide chemistry research, including work that helped identify the next element, mendelevium.
How can an element be discovered in a bomb test?
The immense, brief flood of neutrons released by a thermonuclear explosion can slam into uranium nuclei fast enough to build up much heavier elements before they have time to decay away — a process that doesn't happen under normal reactor conditions. Scientists later found einsteinium and fermium by analyzing debris collected after the Ivy Mike test.
Who is einsteinium named after?
Albert Einstein, honoring his foundational contributions to physics — a fitting tribute given that the element itself was found in the aftermath of a weapon built on physics he helped make possible.
Isotopes
18 known isotopes
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| Isotope | Natural abundance | Half-life | Decay mode | Mass excess | Binding energy / nucleon | Decay width |
|---|---|---|---|---|---|---|
| Es-252 | — | 471.7 d | Alpha decay (78%), Electron capture (22%) | 77,294.61 keV | 7,457.24 keV | 1.12 × 10-23 eV |
| Es-254 | — | 275.7 d | Alpha decay (100%), Beta-minus decay (0.000174%), Spontaneous fission (0.000003%) | 81,994.15 keV | 7,443.58 keV | 1.92 × 10-23 eV |
| Es-255 | — | 39.8 d | Beta-minus decay (92%), Alpha decay (8%), Spontaneous fission (0.0041%) | 84,089.24 keV | 7,437.82 keV | 1.33 × 10-22 eV |
Show all 18 isotopes
| Es-240 | — | 6 s | Alpha decay (70%), Electron capture / beta-plus decay (30%), ECSF (4.8%) | 64,225 keV | 7,481 keV | 7.60 × 10-17 eV |
| Es-241 | — | 8 s | Alpha decay, Electron capture / beta-plus decay | 63,893 keV | 7,485 keV | 5.70 × 10-17 eV |
| Es-242 | — | 17.8 s | Alpha decay (57%), Electron capture / beta-plus decay (43%) | 64,801 keV | 7,483 keV | 2.56 × 10-17 eV |
| Es-243 | — | 21 s | Alpha decay (61%), Electron capture / beta-plus decay (39%), Spontaneous fission (1%) | 64,747 keV | 7,486 keV | 2.17 × 10-17 eV |
| Es-244 | — | 37 s | Electron capture (96%), Alpha decay (4%) | 66,026 keV | 7,483 keV | 1.23 × 10-17 eV |
| Es-245 | — | 1.1 m | Electron capture (60%), Alpha decay (40%) | 66,315 keV | 7,485 keV | 6.91 × 10-18 eV |
| Es-246 | — | 7.5 m | Electron capture / beta-plus decay (90.1%), Alpha decay (9.9%) | 67,818.8 keV | 7,480.78 keV | 1.01 × 10-18 eV |
| Es-247 | — | — | Unknown | 68,578.39 keV | 7,480.1 keV | — |
| Es-248 | — | 24 m | Electron capture (99.7%), Alpha decay (0.25%) | 70,299 keV | 7,476 keV | 3.17 × 10-19 eV |
| Es-249 | — | 102.2 m | Electron capture / beta-plus decay (99.43%), Alpha decay (0.57%) | 71,175 keV | 7,474 keV | 7.44 × 10-20 eV |
| Es-250 | — | 8.6 h | Electron capture (97%), Alpha decay (3%) | 73,225 keV | 7,469 keV | 1.47 × 10-20 eV |
| Es-251 | — | 33 h | Electron capture (99.5%), Alpha decay (0.5%) | 74,511.55 keV | 7,465.88 keV | 3.84 × 10-21 eV |
| Es-253 | — | 20.47 d | Alpha decay (100%), Spontaneous fission (0.0000087%) | 79,010.49 keV | 7,452.89 keV | 2.58 × 10-22 eV |
| Es-256 | — | 25.4 m | Beta-minus decay (100%) | 87,185 keV | 7,428 keV | 2.99 × 10-19 eV |
| Es-257 | — | 7.7 d | Beta-minus decay, Spontaneous fission | 89,403 keV | 7,422 keV | 6.86 × 10-22 eV |