Abstract The kinetics of eighteen positive ions with chlorine azide (ClN3) have been studied using a selected ion flow tube (SIFT). These measurements allowed for the estimation of both the ionization energy, >930 kJ mol−1 (>9.6 eV), and the proton affinity, 713 ± 41 kJ mol−1, of chlorine azide. Reaction rate constants have been determined. Product ions have been identified, and quantified when synthetic complications allowed. In addition, general reaction trends have been observed. A reaction coordinate diagram for the novel reaction of N+ with ClN3 is discussed.