These compounds serve as probes in the Wayne Hubbell pioneered SDSL technique, often using nitroxides. These compounds form stable adducts using traps such as PBN before studying their (-5[1])hyperfine couplings. Autoxidations propagate through these species, which both initiate and are products of hydrogen atom abstractions. Additions to these species are (*) anti-Markovnikov, although their stability follows trends matching that of carbocations (“car-bo-CAT-eye-ons”). Diazo compounds such as AIBN serve as sources for these species. Spin-paired compounds may produce these SOMO-possessing species through homolytic cleavage, especially of dihalogens or peroxides. For 10 points, (10[1])name these unstable species which contain unpaired electrons. ■END■ (10[3])