Information on mass chains and nuclides available on this website:

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¹²Li is not observed in the 4.8 GeV proton bombardment of a uranium target: it is particle unstable (BO74A). Its atomic mass excess is therefore > 49.0 MeV. (TH74) calculate the mass excess of ¹²Li to be 52.92 MeV. ¹²Li would then be unstable with respect to ¹¹Li + n, ¹⁰Li + 2n and ⁹Li + 3n by 3.9, 3.68 and 3.74 MeV, respectively. See also (TH72K, BO73BB, IR74A).