91-Pa-240  basic  element

91-protactinium-240 Atomic Mass: 240.0609800 +- 0.0003200 amu # Excess Mass: 56802.000 +- 298.000 keV # Binding Energy: 1809121.000 +- 298.000 keV # Beta Decay Energy: B- 4093.000 +- 298.000 keV # "The 1995 update to the atomic mass evaluation" by G.Audi and A.H.Wapstra, Nuclear Physics A595 vol. 4 p.409-480, December 25, 1995.