The stability of cationic SF 5 + (SF 6) n−1 clusters was investigated by measuring their blackbody-induced radiative dissociation (BIRD) rates. The clusters were produced in a supersonic expansion ion source and stored in an electrostatic ion-beam trap at room temperature, where their abundances and lifetimes were measured. Using the "master equation" approach, relative binding energies of an SF 6 unit in the clusters could be extracted from the storage-time dependence of the survival probabilities. The results allow for a deeper insight into the effect of a localized charge on the structure and stability of SF 6 -based clusters.