Unhexquadium is a radioactive element that has not been discovered. It will have 164 protons and 318 neutrons. Interest in the chemistry of unhexquadium is largely prompted by predictions that the isotope 482Uhq (with 164 protons and 318 neutrons), would be at the center of a possible second island of stability (the first being centered on 306Ubb or 298Fl ). 