A study of the kinetics of decay of three (Z)-2,2,2-trifluoro-1-arylethanediazoates at 25 degrees C in aqueous media, 4% 2-propanol by volume, ionic strength 1 M (NaClO4) in the pH range 4-13, as well as the results of experiments to detect deuterium incorporation into products from solvent is reported, It is concluded ia the case of the unsubstituted compound that the buffer-independent reaction involves rate-limiting heterolytic bond fission of the diazoic acid to yield a diazonium ion intermediate, and a similar mechanism is indicated for the other two compounds, General acid catalysis of the decay of the diazoic acids at pH < 7 is observed, and it is concluded that the reaction involves rate-limiting N-O bond cleavage of the diazoic acid that is concerted with protonation of the leaving hydroxide ion by the catalyst.