Structure
Not a diagram of dots on rings — a Monte-Carlo sample of the actual probability density |ψ|² for each occupied subshell. Drag to rotate. Blue and violet mark opposite signs of the wavefunction, which is what makes bonding possible.
Measured values
Every bar shows where einsteinium sits among all 118 elements for that property.
Sources: IUPAC 2021 standard atomic weights · CRC Handbook of Chemistry and Physics · NIST. Values marked ~ are predicted rather than measured.
Size, to scale
Radius 245 pm — that is 0.245 nm, so about 2041 million of them side by side would span a millimetre.
Thermal range
Einsteinium is liquid over a 136 K window, from 1133 K to 1269 K.
The story
Discovered in the fallout of the first hydrogen bomb test, in samples flown through the cloud.
Einsteinium was discovered in late 1952 in the debris of the first hydrogen bomb test, representing a dramatic moment when the awesome power of nuclear weapons inadvertently advanced scientific knowledge.
The discovery occurred during analysis of the "Ivy Mike" thermonuclear test:
Discovery was made by scientists from multiple institutions working under extreme secrecy:
Identifying einsteinium required extraordinary analytical skills:
The discovery remained top secret for three years:
The element was named to honor the greatest physicist of the 20th century:
Scientists quickly worked to produce einsteinium in controlled laboratory conditions:
The einsteinium discovery marked a turning point in nuclear science:
Applications
Einsteinium represents the frontier of nuclear science, serving as a crucial bridge to understanding the heaviest elements and pushing the boundaries of atomic physics research.
Einsteinium plays a vital role in creating even heavier elements:
Despite extreme experimental challenges, einsteinium provides unique insights:
Einsteinium serves as an exceptional teaching tool for:
Working with einsteinium drives innovation in:
Einsteinium research contributes to understanding:
Einsteinium research addresses profound questions about:
Einsteinium has no commercial or practical applications outside of specialized nuclear research facilities. Its extreme rarity and short half-life limit all uses to advanced scientific studies.
Extreme Constraints: Research with einsteinium is limited by:
Where it comes from
0 mg/kg of Earth's crust · more abundant than 0% of elements
Einsteinium does not exist in nature and must be created through the advanced nuclear technology available. It represents one of humanity's greatest achievements in atomic engineering.
High-Flux Neutron Bombardment: The primary production method involves intense neutron irradiation:
Einsteinium was first detected in the debris of nuclear weapons tests:
Modern einsteinium production uses sophisticated techniques:
Only a handful of facilities worldwide can produce einsteinium:
Extracting einsteinium requires extraordinary measures:
Total Global Inventory: Less than 1 milligram of einsteinium exists worldwide at any given time, making it one of the rarest substances on Earth.
Handling
Einsteinium is radioactive. It has no stable isotope — every nucleus decays. Handling requires appropriate shielding and licensing.
MAXIMUM DANGER: Einsteinium is among the most radiotoxic materials known to science. All isotopes are highly radioactive with intense alpha and gamma emission.
Einsteinium accidents trigger the highest level emergency response:
CRITICAL WARNING: Even nanogram quantities of einsteinium pose lethal radiation hazards. Only the most qualified nuclear scientists in the advanced facilities should ever handle this material.
Quick answers
Einsteinium (symbol Es) is element 99 on the periodic table, a actinide in period 7. Discovered in the fallout of the first hydrogen bomb test, in samples flown through the cloud. At room temperature it is a solid, and it is radioactive.
[Rn] 5f¹¹ 7s², giving 7 occupied shells holding 2, 8, 18, 32, 29, 8, 2 electrons respectively.Einsteinium melts at 1133 K (859.9 °C) and boils at 1269 K (995.9 °C).
Einsteinium has no stable isotope, so it has no standard atomic weight. The figure quoted, 252, is the mass number of its longest-lived known isotope.
Einsteinium has a density of 8.84 g/cm³. Water is 1.0 g/cm³, so a block of einsteinium is about 8.8× heavier.
Einsteinium has a Pauling electronegativity of 1.3. The scale runs from 0.70 (francium, the least greedy for electrons) to 3.98 (fluorine, the most). Values in this middle band tend to form covalent rather than strongly ionic bonds.
Einsteinium was discovered in 1952 by Ghiorso et al.. It is named after albert Einstein.
Einsteinium does not occur naturally on Earth in any meaningful quantity — it is made in a reactor or an accelerator.
Yes. Einsteinium has no stable isotope — every one of its nuclei decays. It does not occur in usable quantities in nature and must be synthesised.