Elements / 89
89Ac[227]
Actinium
Actinide · f-block · ring Q
Actinium is element 89, an actinide. It is one of the actinides, which the spiral keeps in line on ring Q instead of exiling them to a strip below the table.
Properties
| Density | 10 g/cm³ | Terrain → |
|---|---|---|
| Melting point | 1,500 K · 1,227 °C | Terrain → |
| Boiling point | 3,500 K · 3,227 °C | Terrain → |
| Electronegativity | 1.10 | Terrain → |
| First ionization energy | 499 kJ/mol | Terrain → |
| Atomic weight | 227 u | Terrain → |
| Crustal abundance | 5.5 × 10⁻¹⁰ ppm | Terrain → |
| Discovered | 1902 | Terrain → |
Values from open reference data; see sources. "Terrain" opens that property as a 3D landscape across the whole spiral.
Two things you might not know
- So radioactive that it glows pale blue in the dark, as the particles it emits ionize the surrounding air.
- Named from the Greek for beam or ray; its isotope 225 is studied for targeted alpha therapy against cancer.
Checked against en.wikipedia.org.
Actinides
- Ac Actinium
- Th Thorium
- Pa Protactinium
- U Uranium
- Np Neptunium
- Pu Plutonium
- Am Americium
- Cm Curium
- Bk Berkelium
- Cf Californium
- Es Einsteinium
- Fm Fermium
- Md Mendelevium
- No Nobelium
Ring Q (period 7)
Play with Actinium
Watch it fly into its seat, or raise the whole spiral into a landscape and see where it peaks.