Tl
Thallium
Z 81 204.38 g/molPost-Transition Metal
Nucleus
81 Protons
123 Neutrons
81 Electrons (3 Valence)
Shell distribution: K2 • L8 • M18 • N32 • O18 • P3 • Q0
Electron Configuration
Energy
7p
6d
5f
7s
6p
5d
4f
6s
5p
4d
5s
4p
3d
4s
3p
3s
2p
2s
1s
[Xe]4f145d106s26p1
Oxidation States
CommonRare
0
Pick a state to see its ions
Radii
Empirical
190 pm1.9 Å
Calculated
156 pm1.56 Å
Covalent
145±7 pm1.45±0.07 Å
Van der Waals
196 pm1.96 Å
IonicTl+
150 pm1.5 Å
Crystal Structure
Use the arrow keys to rotate, hold Shift with the left and right arrows to roll, and press Home to reset the view.
Hexagonal close-packedStandard state
Pearson symbol
hP2
Space group
P63/mmc No. 194
Density
11.85 g/cm³