Einsteinium is a synthetic, highly radioactive actinide metal discovered in 1952 in the debris of the first U.S. thermonuclear test. It shows mainly +3 (and sometimes +2) oxidation states and is produced in microgram amounts in specialized reactors.
Einsteinium (Es) is a man-made actinide with atomic number 99. It was first identified in 1952 from radioactive debris of a thermonuclear test, then later produced in reactors for laboratory study. Its name honors Albert Einstein.
Einsteinium resides in the f-block (actinide series), period 7, between californium (Cf) and fermium (Fm). It is distinctive for extreme radioactivity, microgram-scale availability, and self-irradiation that can damage its own crystal lattice and cause self-heating (it can glow faintly in the dark).
The dominant state is +3 (Es(III)); +2 can be stabilized under strongly reducing conditions. Representative compounds include:
A commonly cited ground-state configuration is [Rn] 5f11 7s2. The 5f electrons enable variable bonding and characteristic 3+ chemistry in solution.
Einsteinium is formed via multiple neutron captures and beta decays starting from lighter actinides (such as plutonium, americium, curium, or californium) in high-flux reactors, followed by difficult radiochemical separations. A stylized step is:
\(\cdots \xrightarrow{(n,\gamma)} \mathrm{Cf} \;\xrightarrow{\beta^-}\; \mathrm{Es}\)
Laboratory work often uses isotopes with half-lives on the order of weeks to months, such as Es-253 and Es-254. Short half-lives limit the amount that can be accumulated and complicate precision measurements (e.g., structural and spectroscopic studies).
Yes. Einsteinium has served as a target material to create heavier elements. A historically notable route was the production of mendelevium by alpha-particle bombardment of einsteinium:
\(^{253}\mathrm{Es}(\alpha, n)\,^{256}\mathrm{Md}\)
Such reactions highlight Es’s role in superheavy element research.
Einsteinium is a radiotoxic heavy metal. Primary risks are internal exposure (inhalation/ingestion of particulates), gamma and alpha radiation from isotopes and daughters, and heat from decay. Handling requires licensed hot-cell or glove-box facilities, HEPA-filtered ventilation, remote tools, dosimetry, shielding, and compliant waste management.
In water, Es(III) forms hydrated complexes such as \(\mathrm{[Es(H_2O)_n]^{3+}}\)
Many Es isotopes undergo alpha decay. A representative step is:
\(^{253}\mathrm{Es} \;\to\; ^{249}\mathrm{Bk} + \alpha\)
Successive \(\alpha\)/\(\beta\) decays proceed through neighboring actinides toward longer-lived nuclides.