In situ Raman and ex situ UV-vis provide evidence for the formation of polyiodides (I3 -, I5 -) and I2 during I - oxidation. However, these methods fail to quantify the absolute amount of the species, to locate them in the nanopores, and to clarify whether I2 is a solute or solid. In situ SAXS/WAXS can afford all this (Fig. ).