Actinium Elemental Symbol

French German Italian Portuguese Spanish Swedish
Actinium Actinium Attinio Actínio Actinio Aktinium

Actinium Bohr ModelActinium is an F-Block, Period 7 element. The number of electrons in each of Actinium's shells is 2,8,18,32,18,9,2 and its electron configuration is [Rn] 6d1 7s2. Actinium The actinium atom has a radius of 195 pm. In its elemental form, CAS 7440-34-8, actinium has a silvery-white appearance. Actinium is a radioactive metal that rapidly reacts with the combination of moisture in the air and oxygen to form a white coating of actinium oxide which prevents further oxidation. Actinium is found naturally in uranium ores. It rarely occurs as a free element in the earth’s crust. It can be made in the lab, but it has very minimal important uses. Actinium was first noted as a new element by a French chemist, André-Louis Debierne, in 1899. It was discovered again as an independent element in 1902 by German chemist Friedrich Oskar Giesel.

Actinium information, including Technical Data, Safety Data and its high purity properties, research, applications and other useful facts are discussed below. Scientific facts such as the atomic structure, ionization energy, abundance on Earth, conductivity and thermal properties are included.

  • Properties
  • Research
  • Isotopes
  • Other Elements

Actinium Properties

Symbol: Ac Melting Point: 1050 oC, 1922 oF, 1323.15 K
Atomic Number: 89 Boiling Point: 3200 oC, 5792 oF, 3473.15 K
Atomic Weight: 227 Density: 10060  kg m-3
Element Category: Actinide Liquid Density @ Melting Point: N/A
Group, Period, Block: n/a, 7, f Specific Heat: N/A
    Heat of Vaporization 400 kJ·mol−1
CHEMICAL STRUCTURE Heat of Fusion 14 kJ·mol−1
Electrons: 89 Thermal Conductivity: 12 W·m−1·K−1
Protons: 89 Thermal Expansion: N/A
Neutrons: 139 Electrical Resistivity: N/A
Electron Configuration: [Rn] 6d17s2 Electronegativity: 1.1 (Pauling scale)
Atomic Radius: 215 pm Tensile Strength: N/A
Covalent Radius: N/A Molar Heat Capacity: N/A
Van der Waals radius: N/A Young's Modulus: N/A
Oxidation States: 3 (neutral oxide) Shear Modulus: N/A
Phase: Solid Bulk Modulus: N/A
Crystal Structure: Cubic Poisson Ratio: N/A
Magnetic Ordering: N/A Mohs Hardness: N/A
1st Ionization Energy: 499 kJ·mol−1 Vickers Hardness: N/A
2nd Ionization Energy: 1170 kJ·mol−1 Brinell Hardness: N/A
3rd Ionization Energy: N/A Speed of Sound: N/A
CAS Number: 7440-34-8 Abundance in typical human body, by weight: N/A
ChemSpider ID: 22404 Abundance in typical human body, by atom: N/A
PubChem CID: 23965 Abundance in universe, by weight: N/A
MDL Number: N/A Abundance in universe, by atom: N/A
EC Number: N/A Discovered By: André-Louis Debierne
Beilstein Number: N/A Discovery Date: 1899
SMILES Identifier: [Ac]  
InChI Identifier: InChI=1S/Ac Other Names: Attinio

Recent Research & Development for Actinium

  • Chao Zhang, Zhi-Jian Li, Hong Jiang, Xue-Ning Hu, Guo-Hua Zhong, Yue-Hua Su, Thermodynamic and mechanical properties of actinium and lanthanum dihydride, Journal of Alloys and Compounds, Volume 616, 15 December 2014
  • Hong Jiang, Wei Wang, Chao Zhang, Xue-Ning Hu, Guo-Hua Zhong, Xiao-Qing Lu, Yue-Hua Su, Phase transitions of actinium dihydride: Pressure-induced charge transfer driving effect, International Journal of Hydrogen Energy, Volume 39, Issue 28, 23 September 2014
  • Anpalaki J. Ragavan, Linear free energy relationship applied to trivalent cations with lanthanum and actinium oxide and hydroxide structure, Journal of Nuclear Materials, Volume 358, Issue 1, 15 November 2006
  • F.H. Ruddy, A.R. Dulloo, J.G. Seidel, B. Petrovic, Separation of the alpha-emitting radioisotopes actinium-225 and bismuth-213 from thorium-229 using alpha recoil methods, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Volume 213, January 2004
  • N.A Kulagin, Mixed valency of the rare earth and actinium ions in solid states, Journal of Alloys and Compounds, Volumes 300–301, 12 April 2000
  • J.W. Arblaster, An estimate of the melting point and upper transition temperature of actinium to be used in phase diagrams, Calphad, Volume 19, Issue 3, September 1995
  • V.D. Kosynkin, S.D. Moiseev, V.S. Vdovichev, Cleaning rare earth elements from actinium, Journal of Alloys and Compounds, Volume 225, Issues 1–2, 15 July 1995
  • Michael H. Momeni, Analyses of uranium and actinium gamma spectra: An application to measurements of environmental contamination, Nuclear Instruments and Methods in Physics Research, Volume 193, Issues 1–2, 15 February 1982
  • K. Iyakutti, M. Dakshinamoorthy, R. Asokamani, Bandstructure of actinium and the effect of correlation, Solid State Communications, Volume 40, Issue 5, November 1981
  • F. Weigel, H. Hauske, The lattice constants of actinium(III) oxalate deca-hydrate, Journal of the Less Common Metals, Volume 55, Issue 2, October 1977

Actinium Isotopes

Actinium has no stable isotopes.