Pure Togni reagent II is metastable at room temperature. Heating it above the melting point will lead to strong exothermic decomposition, in which trifluoroiodomethane (CFI) is released. The heat of composition at a temperature of 149 °C and higher has been determined to be 502 J·g. From recrystallization in acetonitrile, small amounts of trifluoromethyl-2-iodobenzoate and 2-iodobenzyl fluoride were observed as decomposition products. Togni reagent II reacts violently with strong bases and acids, as well as reductants. In tetrahydrofuran, the compound polymerizes.