Information on mass chains and nuclides available on this website:

WWW TUNL

²⁰B has not been observed. The mass excess is predicted to be 69.08 MeV (TH74). ²⁰B is then unstable with respect to breakup into ¹⁹B + n by 0.9 MeV [see ¹⁹B]. See also (JA76M, WA76L) and (BE75Q; theor.).