This article says that the alpha decay of bismuth-209 was not listed in any reference table. As much as I hate to disagree, the “Chart of the Nuclides,” 12th edition revised to April 1977, by Knolls Atomic Power Laboratory for Naval Reactors, USDOE, that I have hanging on my wall lists the half-life of bismuth-209 as greater than or equal to 2 x 1018 years with an alpha-particle-decay mode of 3.07 million electronvolts.

James A. Bradbury
Groton, Conn.

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