Symbol Name Atomic Number Atomic Weight Group Number
Th Thorium 90 232.0381


Standard State: solid at 298 K
Color: Silvery white

Discovered by Berzelius in 1828.  Thorium occurs in thorite and in thorianite.   Large deposits of thorium minerals have been reported n New England and elsewhere, but these have not yet been exploited. Thorium is now thought to be about three times as abundant as uranium and about as abundant as lead or molybdenum.  The metal is a source of nuclear power.  There probably more energy available for use from thorium in the minerals of the earth's crust than from both uranium and fossil fuels.  Works has been done is developing thorium cycle converter-reactor systems.