Elements / 81
81Tl204.38
Thallium
Post-transition metal · p-block · ring P · spoke 13
Thallium is element 81, a post-transition metal. It sits on ring P (period 6) on spoke 13, the boron group. Follow that spoke toward the center and out again to find its chemical relatives.
Properties
| Density | 11.8 g/cm³ | Terrain → |
|---|---|---|
| Melting point | 577 K · 304 °C | Terrain → |
| Boiling point | 1,746 K · 1,473 °C | Terrain → |
| Electronegativity | 1.62 | Terrain → |
| First ionization energy | 589 kJ/mol | Terrain → |
| Atomic weight | 204.38 u | Terrain → |
| Crustal abundance | 0.85 ppm | Terrain → |
| Discovered | 1861 | 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
- Its historic popularity as a murder weapon earned it the nicknames the poisoner's poison and inheritance powder.
- Found in 1861 and named from the Greek for green shoot, after its bright green spectral lines. Its sulfate was once rat poison.
Checked against en.wikipedia.org.
Spoke 13: Boron group
Ring P (period 6)
Play with Thallium
Watch it fly into its seat, or raise the whole spiral into a landscape and see where it peaks.