Isotopes of lead

<a href="/facts/Lead/EYljasJN">Lead</a> (82Pb) has four <a href="/facts/Observationally_stable/vC0VVvqN">observationally stable</a> <a href="/facts/Isotope/KD9B1y6o">isotopes</a>: 204Pb, 206Pb, 207Pb, 208Pb. Lead-204 is entirely a <a href="/facts/Primordial_nuclide/lFAUqHDv">primordial nuclide</a> and is not a <a href="/facts/Radiogenic_nuclide/KXP6MKk6">radiogenic nuclide</a>. The three isotopes lead-206, lead-207, and lead-208 represent the ends of three <a href="/facts/Decay_chain/JvTwPNBn">decay chains</a>: the <a href="/facts/Uranium_series/JvTwPNBn">uranium series</a> (or radium series), the <a href="/facts/Actinium_series/JvTwPNBn">actinium series</a>, and the <a href="/facts/Thorium_series/JvTwPNBn">thorium series</a>, respectively; a fourth decay chain, the <a href="/facts/Neptunium_series/JvTwPNBn">neptunium series</a>, terminates with the <a href="/facts/Thallium/v35pGMJB">thallium</a> isotope 205Tl. The three series terminating in lead represent the decay chain products of long-lived primordial <a href="/facts/Uranium-238/QhcHm6q8">238U</a>, <a href="/facts/Uranium-235/pe0RznDM">235U</a>, and <a href="/facts/Thorium-232/lRb3opzg">232Th</a>. Each isotope also occurs, to some extent, as primordial isotopes that were made in supernovae, rather than radiogenically as daughter products. The fixed ratio of lead-204 to the primordial amounts of the other lead isotopes may be used as the baseline to estimate the extra amounts of radiogenic lead present in rocks as a result of decay from uranium and thorium. (See <a href="/facts/Lead%25E2%2580%2593lead_dating/eNnSgyqW">lead–lead dating</a> and <a href="/facts/Uranium%25E2%2580%2593lead_dating/LMCJBhrQ">uranium–lead dating</a>.)
The longest-lived <a href="/facts/Radioisotopes/5WpCfbdq">radioisotopes</a> are 205Pb with a <a href="/facts/Half-life/kGVH8BAB">half-life</a> of 17.3 million years and 202Pb with a half-life of 52,500 years. A shorter-lived naturally occurring radioisotope, 210Pb with a half-life of 22.2 years, is useful for studying the <a href="/facts/Sedimentation/qUgHGvhd">sedimentation</a> chronology of environmental samples on time scales shorter than 100 years.
The relative abundances of the four stable isotopes are approximately 1.5%, 24%, 22%, and 52.5%, combining to give a <a href="/facts/Standard_atomic_weight/8arqbQsq">standard atomic weight</a> (abundance-weighted average of the stable isotopes) of 207.2(1). Lead is the element with the heaviest stable isotope, 208Pb. (The more massive <a href="/facts/Bismuth-209/Bxu7JrUs">209Bi</a>, long considered to be stable, actually has a half-life of 2.01×1019 years.) 208Pb is also a <a href="/facts/Magic_number_(physics)/v9PwXFzQ">doubly magic</a> isotope, as it has 82 <a href="/facts/Proton/clCjepXP">protons</a> and 126 <a href="/facts/Neutron/oRCM1geb">neutrons</a>. It is the heaviest doubly magic nuclide known. A total of 43 lead isotopes are now known, including very unstable synthetic species.
The four primordial isotopes of lead are all <a href="/facts/Observationally_stable/vC0VVvqN">observationally stable</a>, meaning that they are predicted to undergo radioactive decay but no decay has been observed yet. These four isotopes are predicted to undergo <a href="/facts/Alpha_decay/rCsHNIUE">alpha decay</a> and become <a href="/facts/Isotopes_of_mercury/gVVXzNeh">isotopes of mercury</a> which are themselves radioactive or observationally stable.
In its fully ionized state, the <a href="/facts/Beta_decay/vxTBlckp">beta decay</a> of isotope 210Pb does not release a free electron; the generated electron is instead captured by the atom's empty orbitals.

Isotopes of lead open-in-new

Isotopes of lead