We reacted ClO 2 and KO 3 in liquid ammonia and expected the radical coupling to form the compound ClO 2 ···O 3 – . We noted the disappearance of the characteristic red color of the ozonide solution as a clear indication that a reaction took place. Over time, colorless crystals grew, which were unambiguously identified as NH 4 ClO 2 by single‐crystal X‐ray diffraction. This finding has thus provided compelling evidence that, instead of the targeted radical coupling, a one‐electron transfer comprising oxidation of O 3 − had occurred. It further demonstrates that the reduction potential of chlorine dioxide is higher than that of ozone in liquid anhydrous ammonia.
Ressel et al. (Tue,) studied this question.