Lithium-11 is thought to possess a halo nucleus consisting of a core of 3 protons and 8 neutrons, 2 of which have a nuclear halo. It has an exceptionally large cross-section of 3.16 fm, comparable to that of 208Pb. It decays by β- excited nucleus of 11Be, which then decays in several ways (see table below).
Read more about this topic: Isotopes Of Lithium