The kinetics of the oxidation of octacyanomolybdate(IV) by nitrous aci
d has been studied in aqueous perchloric acid medium. An equilibrium c
oncentration of the nitrosonium ion, NO+, has been proposed as the act
ive oxidizing species. An acid dissociation constant for H[Mo(CN)(8)](
3-), K-a = 0.47 +/- 0.05 M at 25 degrees C and I = 1.0 M has been obta
ined from the kinetic data. (C) 1997 Elsevier Science Ltd.