Assertion: thorium's isotope | /r/HasAspect | half-life of 1.39 × 1010 years
Facets:
Source sentences:
text: The isotope 232Th, the parent of one of the radioactive series, has a half-life of 1.39 × 1010 years (the content of isotope 228Th, present in equilibrium with 232Th, being insignificant [1.37 × 10–8percent ]).