Thorium-230 Full table
General
Name, symbol	Thorium-230,230Th
Neutrons	140
Protons	90
Nuclide data
Half-life	75 380 a
Parent isotopes	234U
Decay products	226Ra
Isotope mass	230.0331338 u
Decay mode	Decay energy
Alpha decay	4.77 MeV

Thorium-230 (²³⁰Th) is a radioactive isotope of thorium which can be used to date corals and determine ocean current flux. Ionium was a name given early in the study of radioactive elements to the ²³⁰Th isotope produced in the decay chain of ²³⁸U before it was realized that ionium and thorium are chemically identical. The symbol Io was used for this supposed element. In the science fiction novel "Have Space Suit-Will Travel" by Robert A. Heinlein, there is a conversation between an alien race and humans and the half-life of Thorium-230 (75,380 years) was used as a unit of time.

This isotope-related article is a stub. You can help Wikipedia by expanding it. v • d • e