Stoichiometric equations say nothing about mechanism

The processes that occur in a reaction are not necessarily obvious from the stoichiometric equation. For example, reaction 25.1 might suggest a mechanism involving the direct substitution of coordinated [COy] by H2O. 

However, use of H2 0 as solvent shows that aU the oxygen in the aqua complex is derived from carbonate, and scheme 25.2 shows the proposed pathway of the reaction. 

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