Tm
Thulium
Z 69 168.934 g/molLanthanide
Nucleus
69 Protons
100 Neutrons
69 Electrons (2 Valence)
Shell distribution: K2 • L8 • M18 • N31 • O8 • P2 • Q0
Electron Configuration
Energy
7p
6d
5f
7s
6p
5d
4f
6s
5p
4d
5s
4p
3d
4s
3p
3s
2p
2s
1s
[Xe]4f136s2
Oxidation States
CommonRare
0
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Radii
Empirical
175 pm1.75 Å
Calculated
222 pm2.22 Å
Covalent
190±10 pm1.9±0.1 Å
Van der Waals
227 pm2.27 Å
IonicTm3+
88 pm0.88 Å
Crystal Structure
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Hexagonal close-packed
Pearson symbol
hP2
Space group
P63/mmc No. 194