• Class: AcTinides
• Period: 7
• IUPAC group: 3
• Traditional: IIIa

• Discovered in: 1899 by Debierne
• Origin of name: Greek: aktis, akTinos, (beam or ray)
• Historical or alternate name:

Uranium ores

Soft, Silvery white metal. Reacts with water. Glows in the dark.

• Atmosphere: ~0.0 ppm
• Primitive mantle: ~0.0 ppm
• Sea water: ~0.0 ppm
• Metallic meteorite: ~0.0 ppm
• ConTinental crust: ~0.0 ppm
• Solar photosphere: ~0.0 log of abundance
• Oceanic crust: ~0.0 ppm
• Solar system: ~0.0 relative to Si=1.0e6

   Hazards

Radioactive..

• Lower:
• Upper:

Actinium Physical Properties

 Transitional Data

• State: Solid
• Density: 10.07 g/cm3

 Molar enthalpy

• Atomization: 406.0 kJ mol-1
• Fusion: kJ mol-1
• Vaporization: kJ mol-1

 Transition points

• MelTing point: 1323.0 K
• Boiling point: 3473.0 K
• Critical temperature: 16270.0 K

 Molar properties

• Atomic weight: 227.0278 g/mole
• Molar volume: 22.694 cm3 mol-1

 Crystal structure sequence

face-centered-cubic

 Thermodynamics

• State: solid
  • Enthalpy 0
  • Gibbs function 0
  • Entropy 56.5
  • Heat Capacity 27.2

• State: gas
  • Enthalpy 406
  • Gibbs function 366
  • Entropy 188.1
  • Heat Capacity 20.84

 Miscellaneous physical

• Electrical resistivity: µ-ohms/cm
• Debye temperature: K
• Thermal conductivity: W / m / K
• Coefficient of linear expansion: Coef. per K
• Mass magnetic susceptibility:
• X-ray diffraction mass absorption coefficients:
• CuK: (µ/p)/cm2 g-1
• MoK: (µ/p)/cm2 g-1

Actinium Chemical Properties

 Chemical basics:

• Oxidation states: +3
• Molecular wt: 227.0278 g/mole

 Radii

• Covalent: pm
• Atomic: 188.0 pm
• Van der Waals: pm

 Ions:

• ion: +3 pm 112.0

 Covalent bonds

 Effective nuclear charge

• Slater:
• Clementi:
• Froese-Fischer:

 Electronegativity

• Pauling: 1.1
• Allred-Rochow: 1.00

 Standard reactions

Actinium Nuclear Properties

• Known 11
• Listed 2

• Known 221 - 231
• Listed 225 - 227

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 10.0 days
  • Decay mode: alpha,
  • Source:
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 3/2
• Radioisotopes:
  • Half-life: 20.0 years
  • Decay mode: Beta- alpha,
  • Source:
• Notes

• Isotope 227Cross-section 810±20 barns

• Absolute sensitivity: 1H=1.0
• Relative sensitivity: 1H=1.0
• Receptivity: 13C=1.0
• Magnetogyric ratio: 3.5e7 rad / T / s
• Quadropole moment: 1.7e-28 m2
• Frequency: 13.1 MHz
• Reference:

Actinium Energy Properties

Electrons

• Ground state electron configuration: [Rn] 6d1 7s2
• Electron affinity: kJ mol-1
• Filling orbitals:

 Ionization energies

 Atomic energy levels