Atomic number:89

Group numbers:3

Period:7

Electronic configuration:[Rn] 6d¹ 7s²

Formal oxidation number:+3

Electronegativities:1.1

Atomic radius / pm:188

Relative atomic mass:[227]

 

Actinium was discovered by André-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.

Density / g dm^-3:10060 (calc.)

Molar volume / cm³mol^-1:22.56 (calc.)

Electrical resistivity / μΩcm:- (20 °C)

Thermal conductivity / W m^-1K^-1:12

Melting point / °C:1051

Boiling point / °C:3198

Heat of fusion / kJ mol^-1:-

Heat of vaporization / kJ mol^-1:-

Heat of atomization / kJ mol^-1:406

1st ionization energy / kJ mol^-1:498.83

2nd ionization energy / kJ mol^-1:1167.48

3rd ionization energy / kJ mol^-1:-

in the atmosphere / ppm:-

in the Earth's crust / ppm:-

in the oceans / ppm:-