Zener double exchange process

This exchange, known as Zener double exchange, accounts for an average oxidation state of Co ions (183) at least on the time scale of the reaction of CO oxidation and reaches a maximum for an angle Co-O-Co of 7r-radians (184), i.e., for the cubic structures. It has been suggested that such an average oxidation state of Co facilitates the adsorption-desorption of the reactants, whereas individual Co3+ ions in their discrete spin and oxidation states lead to an adsorption process that is too strong or too weak for the catalytic reaction to take place (183). 

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