Atomic Number:	90
Atomic Symbol:	Th
Atomic Weight:	232.0381
Electron Configuration:	[Rn]7s26d2

Thorium is a source of nuclear power. There is probably moreuntapped energy available for use from thorium in the minerals of theearth's crust than from combined uranium and fossil fuel sources.Much of the internal heat the earth has been attributed to thorium anduranium.

When pure, thorium is a silvery white metal which is air-stable andretains its lustre for several months. When contaminated with theoxide, thorium slowly tarnishes in air, becoming grey and finally black. Thorium oxide has a melting point of 3300°C, the highest of all oxides.Only a few elements, such as tungsten, and a few compounds, such astantalum carbide, have higher melting points.

Thorium is slowly attacked by water, but does not dissolve readily inmost common acids, except
hydrochloric. Powdered thorium metal isoften pyrophoric and should be carefully handled.When heated in air,thorium turnings ignite and burn brilliantly with a white light.