The kinetics of decomposition of [CMC-(MnO42-)-O-VI] intermediate complexes was followed spectrophotometrically at a constant ionic strength of 0.1 mol dm(-3) at 20 C. The reaction was found to be first-order in the concentration of the intermediate complex [Int.] and base-catalyzed. Two rate stages of the decomposition reaction were detected. Activation parameters have been evaluated and discussed. A relevant mechanism for the decomposition of carboxymethyl cellulose was suggested. A new blue hypomanganate(V) coordination polymer intermediate sol was spectrophotometrically detected prior to the formation of the green Sol of manganate(VI) intermediate complex for the first time.,