- 🇬🇧 Actinium
- 🇺🇦 Актиній
- 🇨🇳 錒
- 🇳🇱 Actinium
- 🇫🇷 Actinium
- 🇩🇪 Actinium
- 🇮🇱 אקטיניום
- 🇮🇹 Attinio
- 🇯🇵 アクチニウム
- 🇵🇹 Actínio
- 🇪🇸 Actinio
- 🇸🇪 Aktinium
- 🇷🇺 Актиний
- Name: actinium
- Symbol: Ac
- Atomic number: 89
- Relative atomic mass (Ar): [ 227 ] (longest lived isotope)
- Standard state: solid at 298 K
- Appearance: silvery
- Classification: Metallic
- Group in periodic table:
- Group name: Actinoid
- Period in periodic table: 7 (actinoid)
- Block in periodic table: f
- Shell structure: 2.8.18.32.18.9.2
- CAS Registry: 7440-34-8
Actinium atoms have 89 electrons and the shell structure is 2.8.18.32.18.9.2. The ground state electronic configuration of neutral actinium is [Rn].6d1.7s2 and the term symbol of actinium is 2D3/2.
Actinium: description
Actinium is dangerously radioactive. The chemical behaviour of actinium is similar to that of the rare earths, particularly lanthanum. It is found naturally in uranium ores and actinium is 150 times more radioactive than radium.
actinium
This sample of uraninite contains some about 10-9 grammes of actinium at any one time. Image adapted with permission from Prof James Marshall's (U. North Texas, USA) Walking Tour of the elements CD.
Actinium: physical properties
- Density of the chemical elements on a miniature periodic table spark table Density of solid: 10070 kg m-3
- Molar volume of the chemical elements on a miniature periodic table spark table Molar volume: 22.55 cm3
- Thermal conductivity of the chemical elements on a miniature periodic table spark table Thermal conductivity: 12 (estimate) W m‑1 K‑1
Actinium: heat properties
- Melting point on a miniature periodic table spark table Melting point: 1323 [1050 °C (1922 °F)] K
- Boiling point on a miniature periodic table spark table Boiling point: 3573 [3300 °C (5972 °F)] K
- Enthalpy of fusion on a miniature periodic table spark table Enthalpy of fusion: 20.5 kJ mol-1
Actinium: atom sizes
- Atomic radius (empirical) of the chemical elements on a miniature periodic table spark table Atomic radius (empirical): 195 pm
- Covalent (single bond) radius on a periodic table spark table Molecular single bond covalent radius: 186 (coordination number 3) ppm
- van der Waals radius on a periodic table spark table van der Waals radius: 283 ppm
Actinium: electronegativities
- Pauling electronegativity of the chemical elements on a miniature periodic table spark table Pauling electronegativity: 1.1 (Pauling units)
- Allred-Rochow electronegativity of the chemical elements on a miniature periodic table spark tableAllred Rochow electronegativity: 1.00 (Pauling units)
- Mulliken-Jaffe electronegativity of the chemical elements on a miniature periodic table spark tableMulliken-Jaffe electronegativity: (no data)
Actinium: orbital properties
- First ionization energy the chemical elements on a miniature periodic table spark table First ionisation energy: 519.11 kJ mol‑1
- Second ionization energy the chemical elements on a miniature periodic table spark table Second ionisation energy: 1134 kJ mol‑1
- Third ionization energy the chemical elements on a miniature periodic table spark table Third ionisation energy: 1682 kJ mol‑1
Actinium: abundances
- Chemical elements abundance by weight in the universe on a miniature periodic table spark tableUniverse: (no data) ppb by weight
- Chemical elements abundance by weight in the earth's crust on a miniature periodic table spark tableCrustal rocks: (no data) ppb by weight
- Chemical elements abundance by weight in humans on a miniature periodic table spark tableHuman: (no data) ppb by weight
Actinium: crystal structure
Actinium: biological data
- Human abundance by weight of the chemical elements on a miniature periodic table spark table Human abundance by weight: (no data) ppb by weight
Actinium has no biological role.
Actinium: uses
Actinium: reactions
Reactions of actinium as the element with air, water, halogens, acids, and bases where known.
Actinium: binary compounds
Binary compounds with halogens (known as halides), oxygen (known as oxides), hydrogen (known as hydrides), and other compounds of actinium where known.
Actinium: compound properties
Bond strengths; lattice energies of actinium halides, hydrides, oxides (where known); and reduction potentials where known.
Actinium: history
Actinium was discovered by Andre Debierne in 1899 at France. Origin of name: from the Greek word "aktinos" meaning "ray".Actinium: isotopes
Actinium: isolation
Isolation: coming soon!