Thorium, 90Th
Small (3 cm) ampule with a tiny (5 mm) square of metal in it
Thorium
Pronunciation/ˈθɔːriəm/ (THOR-ee-əm)
Appearancesilvery
Standard atomic weight Ar°(Th)
Thorium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
Ce

Th

actiniumthoriumprotactinium
Atomic number (Z)90
Groupf-block groups (no number)
Periodperiod 7
Block  f-block
Electron configuration[Rn] 6d2 7s2
Electrons per shell2, 8, 18, 32, 18, 10, 2
Physical properties
Phase at STPsolid
Melting point2023 K ​(1750 °C, ​3182 °F)
Boiling point5061 K ​(4788 °C, ​8650 °F)
Density (at 20° C)11.725 g/cm3[3]
Heat of fusion13.81 kJ/mol
Heat of vaporization514 kJ/mol
Molar heat capacity26.230 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 2633 2907 3248 3683 4259 5055
Atomic properties
Oxidation statescommon: +4
−1,[4] +1,? +2,[5] +3[5]
ElectronegativityPauling scale: 1.3
Ionization energies
  • 1st: 587 kJ/mol
  • 2nd: 1110 kJ/mol
  • 3rd: 1930 kJ/mol
Atomic radiusempirical: 179.8 pm
Covalent radius206±6 pm
Color lines in a spectral range
Spectral lines of thorium
Other properties
Natural occurrenceprimordial
Crystal structureface-centered cubic (fcc) (cF4)
Lattice constant
Facecentredcubic crystal structure for thorium
a = 508.45 pm (at 20 °C)[3]
Thermal expansion11.54×10−6/K (at 20 °C)[3]
Thermal conductivity54.0 W/(m⋅K)
Electrical resistivity157 nΩ⋅m (at 0 °C)
Magnetic orderingparamagnetic[6]
Molar magnetic susceptibility132.0×10−6 cm3/mol (293 K)[7]
Young's modulus79 GPa
Shear modulus31 GPa
Bulk modulus54 GPa
Speed of sound thin rod2490 m/s (at 20 °C)
Poisson ratio0.27
Mohs hardness3.0
Vickers hardness295–685 MPa
Brinell hardness390–1500 MPa
CAS Number7440-29-1
History
Namingafter Thor, the Norse god of thunder
DiscoveryJöns Jakob Berzelius (1829)
Isotopes of thorium
Main isotopes[8] Decay
abun­dance half-life (t1/2) mode pro­duct
227Th trace 18.68 d α 223Ra
228Th trace 1.9116 y α 224Ra
229Th trace 7917 y[9] α 225Ra
230Th 0.02% 75400 y α 226Ra
231Th trace 25.5 h β 231Pa
232Th 100.0% 1.405×1010 y α 228Ra
233Th trace 21.83 min β 233Pa
234Th trace 24.1 d β 234Pa
 Category: Thorium
| references
Th · Thorium
Ac ←

ibox Ac

iso
90
Th  [e]
IB-Th [e]
IBisos [e]
→ Pa

ibox Pa

indexes by PT (page)
child table, as reused in {IB-Th}
Main isotopes of thorium
Main isotopes[8] Decay
abun­dance half-life (t1/2) mode pro­duct
227Th trace 18.68 d α 223Ra
228Th trace 1.9116 y α 224Ra
229Th trace 7917 y[9] α 225Ra
230Th 0.02% 75400 y α 226Ra
231Th trace 25.5 h β 231Pa
232Th 100.0% 1.405×1010 y α 228Ra
233Th trace 21.83 min β 233Pa
234Th trace 24.1 d β 234Pa
Data sets read by {{Infobox element}}
Name and identifiers
Symbol etymology (11 non-trivial)
Top image (caption, alt)
Pronunciation
Allotropes (overview)
Group (overview)
Period (overview)
Block (overview)
Natural occurrence
Phase at STP
Oxidation states
Spectral lines image
Electron configuration (cmt, ref)
Isotopes
Standard atomic weight
  most stable isotope
Wikidata
Wikidata *
* Not used in {{Infobox element}} (2023-01-01)
See also {{Index of data sets}} · Cat:data sets (46) · (this table: )

References

  1. ^ "Standard Atomic Weights: Thorium". CIAAW. 2013.
  2. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  3. ^ a b c Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
  4. ^ Th(-I) and U(-I) have been detected in the gas phase as octacarbonyl anions; see Chaoxian, Chi; Sudip, Pan; Jiaye, Jin; Luyan, Meng; Mingbiao, Luo; Lili, Zhao; Mingfei, Zhou; Gernot, Frenking (2019). "Octacarbonyl Ion Complexes of Actinides [An(CO)8]+/− (An=Th, U) and the Role of f Orbitals in Metal–Ligand Bonding". Chemistry (Weinheim an der Bergstrasse, Germany). 25 (50): 11772–11784. 25 (50): 11772–11784. doi:10.1002/chem.201902625. ISSN 0947-6539. PMC 6772027. PMID 31276242.
  5. ^ a b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 28. ISBN 978-0-08-037941-8.
  6. ^ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). CRC Press. pp. 4–135. ISBN 978-0-8493-0486-6.
  7. ^ Weast, R. (1984). CRC, Handbook of Chemistry and Physics. Chemical Rubber Company Publishing. p. E110. ISBN 978-0-8493-0464-4.
  8. ^ a b Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  9. ^ a b Varga, Z.; Nicholl, A.; Mayer, K. (2014). "Determination of the 229Th half-life". Physical Review C. 89 (6): 064310. doi:10.1103/PhysRevC.89.064310.