Thorium

Thorium • Actinide Rare Earth

Symbol: Th
Date of discovery: 1828
Name origin: Scandinavian Thor
Appearance: silvery
Discoverer: Jons Berzelius
Obtained from: monazite, thorite

Melting point: 2023 K
Boiling point: 5063 K
Density[kg/m³]: 11724
Molar volume: 19.80 × 10^-6 m³/mol
Protons/Electrons: 90
Neutrons: 142
Shell structure: 2,8,18,32,18,10,2
Electron configuration: [Rn]6d27s2
Oxidation state: 4
Crystal structure: cubic face centered

Named after Thor, a Scandinavian god of war, thorium is about three times more abundant than uranium. It is found in small amounts in rocks and soils, with abundant supplies in several countries. Monazite, a rare-earth and thorium-phosphate mineral containing twelve percent thorium oxide, is the primary source of the world’s thorium. Similar to uranium, thorium can be used as a fuel in a nuclear reactor and is a key factor in the sustainability of nuclear energy. Much of the earth’s heat is attributed to the decay of both uranium and thorium. When exposed to air, the element retains a silverish white color for about three months then slowly tarnishes to a grey then black color. The primary use of thorium is for strong alloys and ultraviolet photoelectric cells.