Kinetics and thermodynamics of the oxidative-addition reaction of iodine with the dicyanoaurate(I) ion in aqueous solution

Abstract

The equilibrium constant for the reaction Au(CN)₂ ^–+ I₂ Au(CN)₂I₂ ^– has been measured. The reaction obeys the rate expression d[Au(CN)₂I₂ ^–]/dt=k₂[Au(CN)₂ ^–][I₂]+k₂′[Au(CN)₂ ^–][I₃ ^–] with k₂=(2·8 ± 0·2)× 10⁴ l mol^–1 s^–1 and k₂′=(4·40 ± 0·08)× 10⁶ l mol^–1 s^–1 at 25 °C and µ= 0·10M, and is unusual in having k_{I2 /kI3 –= 0·0064 (normally kI2 /kI3 – > 1).}