Atomic number:90
Group numbers:3
Period:7
Electronic configuration:[Rn] 6d2 7s2
Formal oxidation number:+4
Electronegativities:1.3
Atomic radius / pm:179.8
Relative atomic mass:232.03806 ± 0.00002
Thorium was discovered by Jöns Jacob Berzelius (SE) in 1828. Named after Thor, the mythological Scandinavian god of war. It is a heavy, grey, soft, malleable, ductile, radioactive metal that tarnishes in air and reacts with water. It reacts violently with oxidants. Thorium is found in various minerals like monazite and thorite. It is used in making strong alloys, in ultraviolet photoelectric cells. It is a common ingredient in high-quality lenses. When bombarded with neutrons thorium creates uranium-233, a nuclear fuel.
PHYSICAL PROPERTIES
Density / g dm-3:11720 (293 K)
Molar volume / cm3mol-1:19.80 (293 K)
Electrical resistivity / μΩcm:13 (20 °C)
THERMAL PROPERTIES
Thermal conductivity / W m-1K-1:54
Melting point / °C:1750
Boiling point / °C:4788
Heat of fusion / kJ mol-1:19.2
Heat of vaporization / kJ mol-1:513.67
Heat of atomization / kJ mol-1:598.65
IONIZATION ENERGIES
First ionization energy / kJ mol-1:608.51
Second ionization energy / kJ mol-1:1109.59
Third ionization energy / kJ mol-1:1929.72
ABUNDANCE OF ELEMENTS
in the atmosphere / ppm:-
in the Earth's crust / ppm:3.5
in the oceans / ppm:0.0007
CRYSTALLOGRAPHIC DATA
Crystal structure:
face-centered cubic
Unit-cell dimensions / pm:
a=508.42
Space group:
Fm3m
ISOTOPES
REDUCTION POTENTIALS
Th(s)- 1.90 Th(s) + 4OH-- 2.48
| 89 Actinium <= |
90 Thorium
|
=> 91 Protactinium |
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Citing this page:
Generalic, Eni. "Thorium." EniG. Periodic Table of the Elements. 3 Jan. 2012. KTF-Split. {Date of access}. <http://www.periodni.com/th.html>.