Ac
Actinium
Z 89 227.0 g/molActinide Radioactive
Nucleus
89 Protons
138 Neutrons
89 Electrons (3 Valence)
Shell distribution: K2 • L8 • M18 • N32 • O18 • P9 • Q2
Electron Configuration
Energy
7p
6d
5f
7s
6p
5d
4f
6s
5p
4d
5s
4p
3d
4s
3p
3s
2p
2s
1s
[Rn]6d17s2
Radii
Empirical
195 pm1.95 Å
Calculated
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Covalent
215 pm2.15 Å
van Der Waals
260 pm2.6 Å
Oxidation States
CommonRare
0
+2
+3
Crystal Structure
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Face-centered Cubic