The reaction of no with superoxide.

The rate constant for the reaction of NO with .O2- was determined to be (6.7 +/- 0.9) x 10(9) l mol-1 s-1, considerably higher than previously reported. Rate measurements were made from pH 5.6 to 12.5 both by monitoring the loss of .O2- and the formation of the product -OONO. The decay rate of -OONO, in the presence of 0.1 mol l-1 formate, ranges from 1.2 s-1 at pH 5 to about 0.2 s-1 in strong base, the latter value probably reflecting catalysis by formate.