Relative atomic mass: [227]

English: Actinium
French: Actinium
Croatian: Aktinij
German: Actinium
Italian: Attinio
Spanish: Actinio

Atomic number: 89
Group numbers: 3
Period: 7
Standard state (20 oC): solid

Discovery: 1899 Andre-Louis Debierne (FR)
Actinium was discovered by Andre-Louis Debierne (FR) in 1899. The origin of the name comes from the Greek word aktinos meaning ray. It is a heavy, silvery-white, very radioactive metal that reacts with water and glows in the dark. Actinium is extremely rare, found in all uranium ores. It's usually obtained by treating radium with neutrons in a reactor.
Electronic configuration: [Rn] 6d1 7s2
Formal oxidation number: +3
Atomic radius: 188 pm

Electronegativities: 1.1
Thermal conductivity: 12 W/(m K)
Electrical resistivity (20 oC): - microOhm cm

Melting point: 1051 oC
Boiling point: 3198 oC

Heat of fusion: - kJ/mol
Heat of vaporization: - kJ/mol
Heat of atomization: 406 kJ/mol

88Ra <= 89Ac => 90Th

ASCII Periodic Table of the Elements
6 Jan. 2020
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