The versatility of heteropolyanions implies many different uses for Keggin type catalysts. However, new roles for these catalysts must first be preceeded by further understanding of the mechanisms by which they operate. It has been observed that the solvation and/or complexation of heteropolyanions promotes or limits activity in homogeneous chemistry. For this reason the solution state and the solvation characteristics of the catalyst were studied in oxidation and photochemical reactions. Simple oxidation reactions provide a system by which the solution state of the catalyst can be studied. The catalyst used for these mechanistic studies is the Keggin ion (PMo10V2O40)−5.