Thorium superconducting properties

In the area of superconductivity, tetravalent thorium is used to replace trivalent lanthanides in n-ty e doped superconductors, R2 Th Cu0 g, where R = Pr, Nd, or Sm, producing a higher T superconductor. Thorium also forms alloys with a wide variety of metals. In particular, thorium is used in magnesium alloys to extend the temperature range over which stmctural properties are exhibited that are useful for the aircraft industry. More detailed discussions on thorium alloys are available (8,19). 

Properties. Pure thorium metal is a dense, bright silvery metal having a very high melting point. The metal exists in two allotropic modifications. Thorium is a reactive, soft, and ductile metal which tarnishes slowly on exposure to air (12). Having poor mechanical properties, the metal has no direct stmctural appHcations. A survey of the physical properties of thorium is summarized in Table 1. Thorium metal is diamagnetic at room temperature, but becomes superconducting below 1.3—1.4 K. 

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