Natural isotopes


Natural isotopes are either stable isotopes, radioactive isotopes that have a sufficiently long half-life to allow them to exist in substantial concentrations in the Earth, daughter products of those isotopes or cosmogenic elements. The heaviest stable isotope is lead-208, but the heaviest 'natural' isotope is U-238.
Many elements have both natural and artificial isotopes. For example, hydrogen has three natural isotopes and another four known artificial isotopes. A further distinction among stable natural isotopes is division into primordial and cosmogenic elements.

What defines a natural isotope

Natural isotopes must be either stable, have a half-life exceeding about 7 years or are generated in large amounts cosmogenically

Naturally occurring radioisotopes

Some radioisotopes occur in nature with a half-life of less than 7 years. They are synthesised all the time by cosmic radiation. A practical use is radiocarbon dating with carbon-14.