Thorium Elemental Symbol

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Thorium(Th) atomic and molecular weight, atomic number and elemental symbol Thorium is a Elemental ThoriumBlock F, Group 3, Period 7 element. The number of electrons in each of Thorium's shells is 2, 8, 18, 32, 18, 10, 2 and itThorium Bohr Models electron configuration is [Rn] 6d2 7s2. The thorium atom has a radius of and its Van der Waals radius is In its elemental form, CAS 7440-29-1, thorium has a silvery, sometimes black-tarnished, appearance. Thorium was first discovered by Jons Berzelius in 1829. It is found in small amounts in most rocks and soils. The name Thorium originates from the Scandinavian god Thor, the Norse god of war and thunder.

Thorium is a lanthanide (rare earth) material with potential nuclear power applications. It is presently used as a tungsten coating in electronic parts due to its high emission factor. In its fluoride and oxide forms, Thorium is used in advanced optic applications for its high refractive index. It is also used in several other high temperature glass applications, such as in the mantle of lamps and to produce crystal growth crucibles and ampules. High Purity (99.999%) Thorium (Th) Sputtering TargetThorium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). High Purity (99.999%) Thorium Oxide (ThO2) PowderElemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Thorium nanoparticles and nanopowders provide ultra-high surface area which nanotechnology research and recent experiments demonstrate function to create new and unique properties and benefits. Oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Thorium is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Thorium is radioactive and can collect in bones which may cause bone cancer several years after exposure. Breathing in substantial amounts of thorium may be lethal. Safety data for Thorium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab below.

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Thorium Properties

Symbol: Th Melting Point: 2115 K, 1842 °C, 3348 °F
Atomic Number: 90 Boiling Point: 5061 K, 4788 °C, 8650 °F
Atomic Weight: 232 Density: 11.7 g·cm−3
Element Category: Actinide Liquid Density @ Melting Point: N/A
Group, Period, Block: n/a, 7, f Specific Heat: 0.13 kJ/kg K
    Heat of Vaporization 514 kJ·mol−1
CHEMICAL STRUCTURE Heat of Fusion 13.81 kJ·mol−1
Electrons: 90 Thermal Conductivity: 54.0 W·m−1·K−1
Protons: 90 Thermal Expansion: (25 °C) 11.0 µm·m−1·K−1
Neutrons: 142 Electrical Resistivity: (0 °C) 147 nΩ·m
Electron Configuration: [Rn]7s26d2 Electronegativity: 1.3 (Pauling scale)
Atomic Radius: 179 pm Tensile Strength: 144 MPa
Covalent Radius: 206±6 pm Molar Heat Capacity: 26.230 J·mol−1·K−1
Van der Waals radius: 237 pm Young's Modulus: 79 GPa
Oxidation States: 4, 3, 2, 1 (weakly basic oxide) Shear Modulus: 31 GPa
Phase: Solid Bulk Modulus: 54 GPa
Crystal Structure: face-centered cubic Poisson Ratio: 0.27
Magnetic Ordering: paramagnetic Mohs Hardness: 3.0
1st Ionization Energy: 587 kJ·mol−1 Vickers Hardness: 350 MPa
2nd Ionization Energy: 1110 kJ·mol−1 Brinell Hardness: 400 MPa
3rd Ionization Energy: 1930 kJ·mol−1 Speed of Sound: (20 °C) 2490 m·s−1
CAS Number: 7440-29-1 Abundance in typical human body, by weight: N/A
ChemSpider ID: 22399 Abundance in typical human body, by atom: N/A
PubChem CID: 23960 Abundance in universe, by weight: 0.4 ppb
MDL Number: N/A Abundance in universe, by atom: 0.002 ppb
EC Number: 231-139-7 Discovered By: Jöns Jakob Berzelius
Beilstein Number: N/A Discovery Date: 1829
SMILES Identifier: [Th]  
InChI Identifier: InChI=1S/Th Other Names:  

Thorium Products

Metal Forms  •  Compounds  •  Oxide Forms  •  Organometallic Compounds
Sputtering Targets  •  Nanomaterials  •  Semiconductor Materials

Recent Research & Development for Thorium

  • Marisa J. Monreal, Robert K. Thomson, Brian L. Scott, Jaqueline L. Kiplinger, Enhancing the synthetic efficacy of thorium tetrachloride bis(1,2-dimethoxyethane) with added 1,2-dimethoxyethane: Preparation of metallocene thorium dichlorides, Inorganic Chemistry Communications, Volume 46, August 2014
  • Deepak Rawat, Smruti Dash, A.R. Joshi, Thermodynamic studies of thorium phosphate diphosphate and phase investigations of Th-P-O and Th-P-H2O systems, Thermochimica Acta, Volume 581, 10 April 2014
  • M.G. Brik, First-principles studies of the structural, electronic, and optical properties of a novel thorium compound Rb2Th7Se15, Journal of Solid State Chemistry, Volume 212, April 2014
  • Moshiel Biton, Assaf Shamir, Michael Shandalov, Neta Arad-Vosk, Amir Sa'ar, Eyal Yahel, Yuval Golan, Chemical deposition and characterization of thorium-alloyed lead sulfide thin films, Thin Solid Films, Volume 556, 1 April 2014
  • Clément Falaise, Christophe Volkringer, Thierry Loiseau, Isolation of thorium benzoate polytypes with discrete ThO8 square antiprismatic units involved in chain-like assemblies, Inorganic Chemistry Communications, Volume 39, January 2014
  • Yingjie Zhang, Mohan Bhadbhade, Jiabin Gao, Inna Karatchevtseva, Jason R. Price, Gregory R. Lumpkin, Synthesis and crystal structures of uranium (VI) and thorium (IV) complexes with picolinamide and malonamide, Inorganic Chemistry Communications, Volume 37, November 2013
  • A.N. Turanov, V.K. Karandashev, V.M. Masalov, A.A. Zhokhov, G.A. Emelchenko, Adsorption of lanthanides(III), uranium(VI) and thorium(IV) from nitric acid solutions by carbon inverse opals modified with tetraphenylmethylenediphospine dioxide, Journal of Colloid and Interface Science, Volume 405, 1 September 2013
  • K.O. Obodo, N. Chetty, A theoretical study of thorium titanium-based alloys, Journal of Nuclear Materials, Volume 440, Issues 1–3, September 2013
  • Meera Keskar, S.K. Sali, N.D. Dahale, K. Krishnan, N.K. Kulkarni, R. Phatak, S. Kannan, Thermal stability and expansion studies of cesium molybdates and cesium thorium molybdates, Journal of Nuclear Materials, Volume 438, Issues 1–3, July 2013
  • D. Pérez Daroca, S. Jaroszewicz, A.M. Llois, H.O. Mosca, Phonon spectrum, mechanical and thermophysical properties of thorium carbide, Journal of Nuclear Materials, Volume 437, Issues 1–3, June 2013

Thorium Isotopes

Thorium (Th) has six naturally occuring isotopes. None of these are stable; however, 232Th is observationally stable with a half life of 14.05 billion years.

Nuclide Symbol Isotopic Mass Half-Life Nuclear Spin
232Th 232.0380553 1.405(6)×1010 0+