KINETIC-STUDY OF THE REACTION BETWEEN [RE2O3(CN)(8)](4-) AND CYANIDE IONS

A kinetic study of the reaction between [Re2O3(CN)(8)](4-) and cyanide ions indicated that [ReO2(CN)(4)](3-) and [Re(CN)(7)](4-), the final products, are both generated at a rate of 1.30(8) x 10(-4) s(-1) at 38 .2 degrees C and pH = 12. From the nonlinear kinetics, it is deduced t hat cyanide ions react with [Re2O3(CN)(8)](4-) in a fast equilibrium s tep followed by slow decomposition to give [ReO2 (CN)(4)](3-) as the f irst product and [Re(CN)(7)](4-) after a subsequent fast reduction and substitution step. The activation parameters Delta H double dagger 54 (7)kJ mol(-1) and Delta S double dagger = - 145(22) J K-1 mol(-1) were determined.