81
Tl
204.38
Thallium
Element 81 · 204.38 u · p-block
post transition
A highly toxic metal once used in rat poison. Now used in specialized optics and electronics.
Phase (STP)
Solid
Melting Point
304 °C
Boiling Point
1473 °C
Density
11.85 g/cm³
Electronegativity
1.62
Atomic Radius
190 pm
Ionization Energy
589 kJ/mol
Electron Affinity
19 kJ/mol
Discovered
1861 · William Crookes
Electron Configuration
[Xe] 4f14 5d10 6s2 6p1
Electron Orbitals
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