Radium-225

Main isotopes of radium

iso NA half-life DM DE (MeV) DP 223Ra trace 11.43 d α 5.99 219Rn 224Ra trace 3.6319 d α 5.789 220Rn 225Ra trace 14.9 d β− 0.356 225Ac 226Ra trace 1600 y α 4.871 222Rn 228Ra trace 5.75 y β− 0.046 228Ac

Radium (₈₈Ra) has no stable or nearly stable isotopes, and thus a standard atomic weight cannot be given. The longest lived, and most common, isotope of radium is ²²⁶Ra with a half-life of 1,600 years. ²²⁶Ra occurs in the decay chain of ²³⁸U (often referred to as the radium series.) Radium has 33 known isotopes from ²⁰²Ra to ²³⁴Ra.

No fission products
have a half-life
in the range of
100–210 k years ...

... nor beyond 15.7 M years

Legend for superscript symbols
₡  has thermal neutron capture cross section in the range of 8–50 barns
ƒ  fissile
m  metastable isomer
№  naturally occurring radioactive material (NORM)
þ  neutron poison (thermal neutron capture cross section greater than 3k barns)
†  range 4–97 y: Medium-lived fission product
‡  over 200,000 y: Long-lived fission product

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Wikipedia