- 🇬🇧 Thorium
- 🇺🇦 Торій
- 🇨🇳 釷
- 🇳🇱 Thorium
- 🇫🇷 Thorium
- 🇩🇪 Thorium
- 🇮🇱 תוריום
- 🇮🇹 Torio
- 🇯🇵 トリウム
- 🇵🇹 Tório
- 🇪🇸 Torio
- 🇸🇪 Torium
- 🇷🇺 Торий
- Name: thorium
- Symbol: Th
- Atomic number: 90
- Relative atomic mass (Ar): 232.0377 (4) [see note g]
- Standard state: solid at 298 K
- Appearance: silvery white
- Classification: Metallic
- Group in periodic table:
- Group name: Actinoid
- Period in periodic table: 7 (actinoid)
- Block in periodic table: f
- Shell structure: 2.8.18.32.18.10.2
- CAS Registry: 7440-29-1
Thorium atoms have 90 electrons and the shell structure is 2.8.18.32.18.10.2. The ground state electronic configuration of neutral thorium is [Rn].6d2.7s2 and the term symbol of thorium is 3F2.
Thorium: description
Thorium is a source of nuclear power. There is probably more untapped energy available for use from thorium in the minerals of the earth's crust than from combined uranium and fossil fuel sources. Much of the internal heat the earth has been attributed to thorium and uranium.
When pure, thorium is a silvery white metal which is air-stable and retains its lustre for several months. When contaminated with the oxide, thorium slowly tarnishes in air, becoming grey and finally black. Thorium oxide has a melting point of 3300°C, the highest of all oxides. Only a few elements, such as tungsten, and a few compounds, such as tantalum carbide, have higher melting points.
Thorium is slowly attacked by water, but does not dissolve readily in most common acids, except hydrochloric. Powdered thorium metal is often pyrophoric and should be carefully handled.When heated in air, thorium turnings ignite and burn brilliantly with a white light.
Thorium is named for Thor, the Scandinavian god of war. It is found in thorite and thorianite in New England (USA) and other sites.
thorium
Image adapted with permission from Prof James Marshall's (U. North Texas, USA) Walking Tour of the elements CD.
Thorium: physical properties
- Density of the chemical elements on a miniature periodic table spark table Density of solid: 11724 kg m-3
- Molar volume of the chemical elements on a miniature periodic table spark table Molar volume: 19.80 cm3
- Thermal conductivity of the chemical elements on a miniature periodic table spark table Thermal conductivity: 54 W m‑1 K‑1
Thorium: heat properties
- Melting point on a miniature periodic table spark table Melting point: 2115 [1750 °C (3182 °F)] K
- Boiling point on a miniature periodic table spark table Boiling point: 5093 [4820 °C (8708 °F)] K
- Enthalpy of fusion on a miniature periodic table spark table Enthalpy of fusion: 20.5 kJ mol-1
Thorium: atom sizes
- Atomic radius (empirical) of the chemical elements on a miniature periodic table spark table Atomic radius (empirical): 180 pm
- Covalent (single bond) radius on a periodic table spark table Molecular single bond covalent radius: 175 (coordination number 4) ppm
- van der Waals radius on a periodic table spark table van der Waals radius: [ 305 ] ppm
Thorium: electronegativities
- Pauling electronegativity of the chemical elements on a miniature periodic table spark table Pauling electronegativity: 1.3 (Pauling units)
- Allred-Rochow electronegativity of the chemical elements on a miniature periodic table spark tableAllred Rochow electronegativity: 1.11 (Pauling units)
- Mulliken-Jaffe electronegativity of the chemical elements on a miniature periodic table spark tableMulliken-Jaffe electronegativity: (no data)
Thorium: orbital properties
- First ionization energy the chemical elements on a miniature periodic table spark table First ionisation energy: 608.50 kJ mol‑1
- Second ionization energy the chemical elements on a miniature periodic table spark table Second ionisation energy: 1167 kJ mol‑1
- Third ionization energy the chemical elements on a miniature periodic table spark table Third ionisation energy: 1768 kJ mol‑1
Thorium: abundances
- Chemical elements abundance by weight in the universe on a miniature periodic table spark tableUniverse: 0.4 ppb by weight
- Chemical elements abundance by weight in the earth's crust on a miniature periodic table spark tableCrustal rocks: 6000 ppb by weight
- Chemical elements abundance by weight in humans on a miniature periodic table spark tableHuman: (no data) ppb by weight
Thorium: crystal structure
Thorium: 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
Thorium has no biological role.
Thorium: uses
Thorium: reactions
Reactions of thorium as the element with air, water, halogens, acids, and bases where known.
Thorium: binary compounds
Binary compounds with halogens (known as halides), oxygen (known as oxides), hydrogen (known as hydrides), and other compounds of thorium where known.
Thorium: compound properties
Bond strengths; lattice energies of thorium halides, hydrides, oxides (where known); and reduction potentials where known.
Thorium: history
Thorium was discovered by Jöns Berzelius in 1829 at Sweden. Origin of name: named after "Thor", the mythological Scandinavian god of war.Thorium: isotopes
Thorium: isolation
Isolation: coming soon!