The kinetics of the reaction of aquomanganese(III) ions with hydrazoic acid in perchlorate media

Abstract

The reaction of aquomanganese(III) ions with hydrazoic acid in perchlorate media is of the first order in total [Mn^III] and second order in [HN₃], and one Mn^III ion is consumed for every HN₃ molecule which disappears. The observed third-order rate constant increases with increasing acidity. This is interpreted by the reaction of a hydrazidopentaquomanganese(III) ion, Mn(H₂O)₅HN₃³⁺, with HN₃ to produce an azide radical H₂N₆^+·, which then reacts rapidly with another Mn^III ion to produce molecular nitrogen. The energy and entropy of activation are determined. The significance of hydrazido-complexes in the aquation of azido-complexes is discussed.