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A hypothetical metallic state of thorium that had the [Rn]6d 2 7s 2 configuration with the 5f orbitals above the Fermi level should be hexagonal close packed like the group 4 elements titanium, zirconium, and hafnium, and not face-centred cubic as it actually is. The actual crystal structure can only be explained when the 5f states are invoked ...
Thorium reacts with hydrogen to form the thorium hydrides ThH 2 and Th 4 H 15, the latter of which is superconducting below the transition temperature of 7.5–8 K; at standard temperature and pressure, it conducts electricity like a metal. [12] Thorium is the only metallic element that readily forms a hydride higher than MH 3. [31]
Thorium resources are the estimated mineral reserves of thorium on Earth. Thorium is a future potential source of low-carbon energy. [1] Thorium has been demonstrated to perform as a nuclear fuel in several reactor designs. [2] [3] It is present with a higher abundance than uranium in the crust of the earth. Thorium resources have not been ...
Metallic thorium is separated from the anhydrous oxide, chloride or fluoride by reacting it with calcium in an inert atmosphere: [78] ThO 2 + 2 Ca → 2 CaO + Th. Sometimes thorium is extracted by electrolysis of a fluoride in a mixture of sodium and potassium chloride at 700–800 °C in a graphite crucible.
Under some definitions, the value of the radius may depend on the atom's state and context. [1] Atomic radii vary in a predictable and explicable manner across the periodic table. For instance, the radii generally decrease rightward along each period (row) of the table, from the alkali metals to the noble gases; and increase down each group ...
Thorium is a weakly radioactive light silver metal which tarnishes olive grey when it is exposed to air, forming thorium dioxide; it is moderately soft, malleable, and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely ...
Thorium was also used in certain glass elements of Aero-Ektar lenses made by Kodak during World War II. Thus they are mildly radioactive. [15] Two of the glass elements in the f/2.5 Aero-Ektar lenses are 11% and 13% thorium by weight. The thorium-containing glasses were used because they have a high refractive index with a low dispersion ...
Monazite contains 2.5% thorium, allanite has 0.1 to 2% thorium and zircon can have up to 0.4% thorium. [2] Thorium-containing minerals occur on all continents. [3] [4] [5] Thorium is several times more abundant in Earth's crust than all isotopes of uranium combined and thorium-232 is several hundred times more abundant than uranium-235. [6]