Thorium

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Thorium
90Th
Ce

Th

(Uqb)
actiniumthoriumprotactinium
Appearance
sillery, eften wi black tarnish
General properties
Name, seembol, nummer thorium, Th, 90
Pronunciation /ˈθɔəriəm/
THAWR-ee-əm
Element category actinide
Group, period, block n/a, 7, f
Staundart atomic wicht 232.0377(4)
Electron confeeguration [Rn] 6d2 7s2
2, 8, 18, 32, 18, 10, 2
Electron shells of thorium (2, 8, 18, 32, 18, 10, 2)
History
Discovery Jöns Jakob Berzelius (1829)
Physical properties
Phase solid
Density (near r.t.) 11.7 g·cm−3
Meltin pynt 2115 K, 1842 °C, 3348 °F
Boilin pynt 5061 K, 4788 °C, 8650 °F
Heat o fusion 13.81 kJ·mol−1
Heat o vaporization 514 kJ·mol−1
Molar heat capacity 26.230 J·mol−1·K−1
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 states 4, 3, 2, 1

(weakly basic oxide)

Electronegativity 1.3 (Pauling scale)
Ionization energies 1st: 587 kJ·mol−1
2nd: 1110 kJ·mol−1
3rd: 1930 kJ·mol−1
Atomic radius 179 pm
Covalent radius 206±6 pm
Miscellanea
Crystal structure face-centered cubic
Thorium has a face-centered cubic crystal structure
Magnetic orderin paramagnetic[1]
Electrical resistivity (0 °C) 147 nΩ·m
Thermal conductivity 54.0 W·m−1·K−1
Thermal expansion (25 °C) 11.0 µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 2490 m·s−1
Young's modulus 79 GPa
Shear modulus 31 GPa
Bulk modulus 54 GPa
Poisson ratio 0.27
Mohs hairdness 3.0
Vickers hairdness 350 MPa
Brinell hairdness 400 MPa
CAS registry nummer 7440-29-1
Most stable isotopes
Main article: Isotopes o thorium
iso NA hauf-life DM DE (MeV) DP
228Th trace 1.9116 y α 5.520 224Ra
229Th trace 7340 y α 5.168 225Ra
230Th trace 75380 y α 4.770 226Ra
231Th trace 25.5 h β 0.39 231Pa
232Th 100% 1.405×1010 y α 4.083 228Ra
234Th trace 24.1 d β 0.27 234Pa
· r

Thorium is a naiturally occurrin radioactive chemical element wi the seembol Th an atomic nummer 90. It wis discovered in 1828 bi the Norwegian mineralogist Morten Thrane Esmark an identified bi the Swadish chemist Jöns Jakob Berzelius an named efter Thor, the Norse god o thunner.

References[eedit | eedit soorce]

  1. Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.