← Periodic Table
89
f🧱
Ac
227.0000

Actinium

Actinide

Atomic Properties

Atomic Number
89
Atomic Mass
227.0000 u
Electron Configuration
[Rn] 6d1 7s2
Electronegativity
1.10
Block
f-block
Group
Period
7

🌡 Physical Properties

Phase (STP)
solid
Melting Point
1500.00 K
Boiling Point
3500.00 K
Density
10.0000 g/cm³

About Actinium

First actinide; highly radioactive; glows blue in the dark.

🔬 Isotopes of Actinium

Actinium has 0 naturally occurring isotopes, plus 1 notable radioactive isotope.

IsotopeMass NumberAtomic Mass (u)AbundanceType
227Ac227227.0277523Radioactive

Data source: NIH PubChem (aggregated from IUPAC, NIST)