Inorganic Gas-Phase Reactions of the Nitrate Radical: I2 + NO3 and I + NO3

Article abstract of DOI:10.1021/j100187a028

A low-pressure discharge-flow technique, with various optical detection methods, has been used to determine, for the first time, bimolecular rate coefficients for the reactions between I2 and NO3, k₁ = (1.5 +/- 0.5) * 1E-12 cm³ molecule^-1 s^-1, and I and NO3, k₂ = (4.5 +/- 1.9) * 1E-10 cm³ molecule^-1 s^-1.No temperature dependence over the range 292-423 K, or pressure dependence from 1.2 to 4.7 Torr, was observed for the reaction I2 + NO3.A heterogeneous generation of I atoms was observed in the I + NO3 reaction system which was interpreted as evidence for the reaction of IO at the surface of the flow reactor to form a higher oxide of iodine and iodine atoms.The rate coefficient for reaction of IO at the walls to form I was found to be 25-45 s^-1.An upper limit for the heat of formation of IONO2 of 21 +/- 3 kJ mol^-1 was also derived.