The gas-phase ozonation of a series of alkenes RCHCH2 (R= Et, Hex), trans-RHCCHR (R= Me, Et, Pri) and Me2CCMe2 at–40 to 20° C, and that of ethene H2CCH2 at–120 to 0° C at 10–4 v/v concentrations in N2 at atmospheric pressure have been studied. Using complementary product analysis by means of GC–FTIR and GC–MS techniques, we present conclusive evidence for the formation of secondary alkene ozonides as high-yield ...