F. Cacace et M. Speranza, PROTONATED OZONE - EXPERIMENTAL DETECTION OF O3H+ AND EVALUATION OF THE PROTON AFFINITY OF OZONE, Science, 265(5169), 1994, pp. 208-209
The elusive protonated ozone ion (O3H+) has been long postulated as a
reactive intermediate but never experimentally observed. This ion has
been detected here in mass spectrometric experiments with the use of F
ourier transform ion cyclotron resonance. In these experiments, ozone
(O-3) was protonated by strong acids-for example, H-3(+), KrH1+ XeH+,
and CH5+. The hitherto experimentally unknown proton affinity of O-3 w
as evaluated by a ''bracketing'' technique and determined to be 148 +/
- 3 kilocalories mole(-1) at 298 kelvin, in excellent agreement with a
value determined in a recent theoretical study of the O-3/O3H+ system
, which was 148 kilocalories mole(-1) at zero temperature (similar to
149.5 kilocalories mole(-1) at 298 kelvin).