A metallic element found in certain rare minerals, as thorite, pyrochlore, monazite, etc., and isolated as an infusible gray metallic powder which burns in the air and forms thoria; -- formerly called also thorinum. Symbol Th. Atomic weight 232.0.
An element that is a byproduct of the decay of uranium.
See table. ... : an isotope of polonium produced in thorium decay, namely 216Po (half-life = 0.15 s).[ Soddy] ... : The names of two radioisotopes, both produced in thorium decay, included thorium C. Simple thorium C was an isotope of bismuth, namely 212Bi (half-life = 61 min); thorium C' was an isotope of polonium, namely 212Po (half-life = 0.3 µs) [ Rutherford, Soddy] ... : an isotope of thallium produced in thorium decay, namely 208Tl (half-life = 3 min). [Soddy & ] ... : an isotope of radium produced in thorium decay, namely 224Ra (half-life = 3.6 d). [ Rutherford, Soddy
a soft silvery-white tetravalent radioactive metallic element; isotope 232 is used as a power source in nuclear reactors; occurs in thorite and in monazite sands
a naturally occurring radioactive metal found in small amounts in soil, rocks, water, plants, and animals. The most common isotopes of thorium are thorium-232 (Th-232), thorium-230 (Th-230), and thorium-238 (Th-238).
A chemical element, Th, that has an atomic number 90. It is used in the manufacturing of sun lamps.
A naturally-occurring radioactive element and one of four primary radionuclides in FUSRAP wastes. They include radium-226, radon-222, uranium-234, uranium-235 and uranium-238.
Thorium (IPA: ) is a chemical element in the periodic table that has the symbol Th and atomic number 90. As a naturally occurring, slightly radioactive metal, it has been considered as an alternative nuclear fuel to uranium.