The three naturally-occurring actinide alpha decay chains given below—thorium, uranium/radium (from U-238), and actinium (from U-235)—each ends with its own specific lead isotope (Pb-208, Pb-206, and Pb-207 respectively).
De tre naturligt forekommende aktinid alfa henfaldskæder som er vist herunder - thorium, uran/radium (fra U-238) og actinium (fra U-235) - ender hver i deres bestemte bly-isotop (henholdsvis Pb-208, Pb-206 og Pb-207).