// MATTER · ELEMENT 85 / 118atoms.no/elements
At85
Astatine
At·Z 85·Halogen·210·⭕ 8B · C Major
▸ The reading
interpretive · artAstatine is the rarest natural element on Earth — estimates span milligrams to tens of grams crust-wide, and never twice the same atoms, each decaying in milliseconds to seconds; ²¹⁹At, nature's longest-lived, lasts 56 seconds. Medicine aims its alpha particles at tumours as ²¹¹At — cyclotron-made, half-life 7.2 hours. A whole seat at the table held by a population that never stops turning over.
The science below is cited as science; the symbolic layers are flagged as interactive art.
⚜ Periodic Frequency
8BC Major
a seat struck in brass — testimony, not prediction
the seat has its own room on ⭕ THE OVAL TABLE — tap the code
▸ The lenses
▸ Discovery
Dale Corson + Kenneth Ross MacKenzie + Emilio Segrè — produced by alpha-bombarding bismuth in a cyclotron · United States · 1940
▸ Stellar origin
Decay product (extremely transient)All astatine isotopes are radioactive; longest-lived has a half-life of 8.1 hours. Less than 30 grams of astatine exists in Earth's crust at any moment.
▸ Reactivity
Heaviest halogen; chemistry inferred from microscopic samplesMost properties known only by analogy to iodine or by spectroscopy of trace amounts — bulk astatine has never existed long enough to weigh.
▸ Applications
- Targeted alpha-particle cancer therapy (²¹¹At)
- Radiochemistry research
- Halogen-series chemistry studies
- Trace nuclear-medicine tracer
▸ Curiosity
Rarest naturally occurring element on Earth — estimates of the crustal total run from under a gram to about 28 g at any moment, and never twice the same atoms.
▸ Related readings
a resonance drawn between readings — not a claim that they share an origin.
Group 17IIodineTsTennessine
Period 6PoPoloniumRnRadon
p-blockPoPoloniumRnRadon
Adjacent ZPoPoloniumRnRadon