Description:
<jats:title>Abstract</jats:title><jats:p>Recent progress in understanding the phase‐dependent reactivity of halooxides and nitrosyl halides is outlined. Halooxide reactivity is represented by the photochemistry of chlorine dioxide (OCIO) and dichlorine monoxide (CIOCI). The gas phase photochemical dynamics of OCIO are contrasted with the dynamics in condensed environments. The role of excited‐state symmetry in defining the reaction dynamics and the observation of photoisomerization resulting in the production of CIOO are discussed. The current understanding of the excited‐state reaction dynamics of CIOCI and evidence for photoisomerization of this species resulting in the production of CICIO are outlined. Finally, the photochemical reaction dynamics of the nitrosyl halide CINO are presented. The main difference between the gas and condensed phase reaction dynamics of this species is that whereas photodissociation to form CI and NO dominates the gas phase reaction dynamics, photoisomerization resulting in CION production occurs to an appreciable extent in condensed environments. The observation of photoisomerization for OCIO, CIOCI and CINO suggests that this process is a general feature of the condensed phase reaction dynamics for smaller halooxides and nitrosyl halides. Finally, future areas for study in both halooxide and nitrosyl halide photoreactivity are outlined.</jats:p>