// MATTER · ELEMENT 87 / 118atoms.no/elements
Fr87
Francium
Fr·Z 87·Alkali Metal·223·⭕ 10B · D Major
▸ The reading
interpretive · artFrancium was discovered by Marguerite Perey, who entered science as Marie Curie's lab assistant and left it as the first woman elected a corresponding member of the French Academy of Sciences. Her element was expected to out-react caesium, but relativity grips its outer electron tighter, and it has never existed in bulk. Potential energy, in both the person and the atom.
The science below is cited as science; the symbolic layers are flagged as interactive art.
⚜ Periodic Frequency
10BD 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
Marguerite Perey — observed the decay of actinium at the Curie Institute · France · 1939
▸ Stellar origin
Decay product (essentially nonexistent in nature)Longest-lived isotope ²²³Fr has a 22-minute half-life. At any moment, less than 30 grams of francium exists naturally on the planet.
▸ Reactivity
Long called the most reactive metal — relativity says otherwisePeriodic trends predicted it would out-react cesium, but its measured ionization energy is higher (393.0 vs 375.7 kJ/mol) — relativistic stabilization of the 7s electron leaves cesium more reactive; bulk francium has never been assembled.
▸ Applications
- Atomic-physics research (laser cooling)
- Tests of fundamental symmetry
- Heaviest alkali for spectroscopy comparisons
- (No practical applications)
▸ Curiosity
Discovered by Marguerite Perey, who began as Marie Curie's lab assistant and later became the first woman elected a corresponding member of the French Academy of Sciences.
▸ Related readings
a resonance drawn between readings — not a claim that they share an origin.