Technical data for Actinium

Overview
NameActinium
SymbolAc
Atomic Number89
Atomic Weight227[note]
Density10.07 g/cm3
Melting Point1050 °C
Boiling Point3200 °C

Thermal properties
PhaseSolid
Melting Point1050 °C
Boiling Point3200 °C
Absolute Melting Point1323 K
Absolute Boiling Point3473 K
Heat of Fusion14 kJ/mol
Heat of Vaporization400 kJ/mol
Heat of CombustionN/A
Specific Heat120 J/(kg K)[note]
Thermal Conductivity12 W/(m K)
Thermal ExpansionN/A

Bulk physical properties
Density10.07 g/cm3
Density (Liquid)N/A
Molar Volume0.0000225422
Thermal Conductivity12 W/(m K)
Thermal ExpansionN/A

Reactivity
Valence3
Electronegativity1.1
ElectronAffinityN/A
Ionization Energies
499, 1170 kJ/mol

Health and Safety
Autoignition PointN/A
FlashpointN/A

Classifications
Alternate NamesNone
Nams of AllotropesNone
Blockf
GroupN/A
Period7
Electron Configuration[Rn]6d17s2
ColorSilver
Discovery
1899 in France
Gas phaseN/A
CAS NumberCAS7440-34-8

Electrical properties
Electrical TypeN/A
Electrical ConductivityN/A
ResistivityN/A
Superconducting PointN/A

Magnetic properties
Magnetic TypeN/A
Curie PointN/A
Mass Magnetic SusceptibilityN/A
Molar Magnetic SusceptibilityN/A
Volume Magnetic SusceptibilityN/A

Abundances
% in UniverseN/A
% in SunNone
% in MeteoritesN/A
% in Earth's CrustN/A
% in OceansN/A
% in HumansNone

Atomic dimensions and structure
Atomic RadiusN/A
Covalent RadiusN/A
Van der Waals RadiusN/A
Crystal StructureFace Centered Cubic
Lattice Angles
π/2, π/2, π/2
Lattice Constants
567, 567, 567 pm
Space Group NameFm_ 3m
Space Group Number225

Nuclear Properties
Half-Life21.7865 y
Lifetime31.4311 y

Notes on the properties of Actinium:
Atomic Weight: Atomic mass number given for longest lived isotope.
Specific Heat: Value given for solid phase.