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Technical data for Thorium

Click any property name to see plots of that property for all the elements.

Overview
NameThorium
SymbolTh
Atomic Number90
Atomic Weight232.0381
Density11.724 g/cm3
Melting Point1750 °C
Boiling Point4820 °C

Thermal properties
PhaseSolid
Melting Point1750 °C
Boiling Point4820 °C
Absolute Melting Point2023 K
Absolute Boiling Point5093 K
Critical PressureN/A
Critical TemperatureN/A
Heat of Fusion16 kJ/mol
Heat of Vaporization530 kJ/mol
Heat of CombustionN/A
Specific Heat118 J/(kg K)[note]
Adiabatic IndexN/A
Neel PointN/A
Thermal Conductivity54 W/(m K)
Thermal Expansion0.000011 K-1

Bulk physical properties
Density11.724 g/cm3
Density (Liquid)N/A
Molar Volume0.0000197917
Brinell Hardness400 MPa
Mohs Hardness3 MPa
Vickers Hardness350 MPa
Bulk Modulus54 GPa
Shear Modulus31 GPa
Young Modulus79 GPa
Poisson Ratio0.27
Refractive IndexN/A
Speed of Sound2490 m/s
Thermal Conductivity54 W/(m K)
Thermal Expansion0.000011 K-1

Reactivity
Valence4
Electronegativity1.3
ElectronAffinityN/A
Ionization Energies
587, 1110, 1930, 2780 kJ/mol

Health and Safety
Autoignition Point130 °C
FlashpointN/A
Heat of CombustionN/A
DOT Hazard Class7
DOT Numbers2975
EU NumberEU231-139-7
NFPA Fire RatingN/A
NFPA HazardsN/A
NFPA Health RatingN/A
NFPA Reactivity RatingN/A
RTECS NumberRTECSXO6400000
NFPA LabelN/A

Classifications
Alternate NamesNone
Names of AllotropesNone
Blockf
GroupN/A
Period7
Electron Configuration[Rn]6d27s2
ColorSilver
Discovery
1829 in Sweden
Gas phaseN/A
CAS NumberCAS7440-29-1
CID NumberCID23960
Gmelin NumberGmelin16314
NSC NumberN/A
RTECS NumberRTECSXO6400000

Electrical properties
Electrical TypeConductor
Electrical Conductivity6.7×106 S/m
Resistivity1.5×10-7 m Ω
Superconducting Point1.38

Magnetic properties
Magnetic TypeParamagnetic
Curie PointN/A
Mass Magnetic Susceptibility7.2×10-9
Molar Magnetic Susceptibility1.7×10-9
Volume Magnetic Susceptibility0.000084

Abundances
% in Universe4×10-8%
% in Sun3×10-8%
% in Meteorites3.9×10-6%
% in Earth's Crust0.0006%
% in Oceans4×10-12%
% in HumansNone

Atomic dimensions and structure
Atomic RadiusN/A
Covalent RadiusN/A
Van der Waals RadiusN/A
Crystal StructureFace Centered Cubic
Lattice Angles
π/2, π/2, π/2
Lattice Constants
508.42, 508.42, 508.42 pm
Space Group NameFm_ 3m
Space Group Number225

Nuclear Properties
Half-Life1.406×1010 y
Lifetime2.0285×1010 y
Decay ModeAlphaEmission
Quantum Numbers3F2
Neutron Cross Section7.4
Neutron Mass Absorption0.001
Known Isotopes
209Th, 210Th, 211Th, 212Th, 213Th, 214Th, 215Th, 216Th, 217Th, 218Th, 219Th, 220Th, 221Th, 222Th, 223Th, 224Th, 225Th, 226Th, 227Th, 228Th, 229Th, 230Th, 231Th, 232Th, 233Th, 234Th, 235Th, 236Th, 237Th, 238Th
Stable Isotopes
232Th
Isotopic Abundances
232Th100%


Notes on the properties of Thorium:

Specific Heat: Value given for solid phase.

Up to date, curated data provided by
Mathematica's ElementData function from Wolfram Research, Inc.

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