Information on mass chains and nuclides available on this website:

WWW TUNL

¹⁸B has not been observed: it is predicted to have a mass excess of 53.85 MeV. ¹⁸B is then unstable with respect to ¹⁷B + n by 1.39 MeV (JA76M; and see (WA76L)). See also (TH74) and (BE75Q; theor.).