text: The 4n+3 chain of uranium-235 is commonly called the "actinium series" or "actinium cascade". Beginning with the naturally-occurring isotope uranium-235, this decay series includes the following elements:  actinium, astatine, bismuth, francium, lead, polonium, protactinium, radium, radon, thallium, and thorium. All are present, at least transiently, in any sample containing uranium-235, whether metal, compound, ore, or mineral. This series terminates with the stable isotope lead-207.
  In the early Solar System this chain went back to Cm. This manifests itself today as variations in U/U ratios, since curium and uranium have noticeably different chemistries and would have separated differently.
  The total energy released from uranium-235 to lead-207, including the energy lost to neutrinos, is 46.4 MeV.