isotopes204Pb

Lead-204, denoted 204Pb, is a stable isotope of the element lead (Pb) with 82 protons and 122 neutrons, giving it a mass number of 204. It is one of the four stable lead isotopes, the others being 206Pb, 207Pb and 208Pb. In natural lead, 204Pb accounts for about 1.4% of the total lead, with small variations among samples.

204Pb is a primordial nuclide, not produced by the radioactive decay of a longer-lived parent in the present geologic system. Its existence, together with the radiogenic isotopes 206Pb, 207Pb and 208Pb, reflects the initial composition of lead since the formation of the solar system and is influenced by stellar nucleosynthesis processes.

In geochemistry and geochronology, 204Pb serves as a non-radiogenic reference isotope for Pb-Pb dating and related isotopic studies. Ratios such as 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb are used to quantify radiogenic ingrowth and to model the age and evolutionary history of rocks, minerals, and meteorites. Isotope measurements are typically performed using mass spectrometry techniques, including thermal ionization mass spectrometry and inductively coupled plasma mass spectrometry.