90
Thorium
Atomic Number90
Atomic Mass232.0 u
CategoryActinide
State at Room TempSolid
Year Discovered1829
About Thorium
Named after Thor, the Norse god of thunder. Thorium oxide glowed white in gas lamp mantles for a century. A fertile nuclear fuel that breeds uranium-233, thorium reactors are championed as safer and more abundant alternatives to uranium, and India, sitting on huge reserves, runs a serious program. Hundreds of times more common in crust than uranium and far harder to weaponize.
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