Spectrophotometric studies of reduced molybdoantimonylphosphoric acid

Spectrophotometric studies have been used to determine the optimal formation conditions and stoichiometry of the reduced molybdoantimonylphosphoric acid. It was found that a H⁺]/MoO^2-₄] ratio of70± 10 was optimal for formation between 0.0008 and 0.01 M molybdenum. This corresponds to solution conditions that favor the existence of the dimeric form of molybdenum. The H⁺]/MoO^2-₄] criteria allows simple variation of experimental conditions. The stoichiometry of the reduced heteropoly acid was surmised to be PSb₂Mo₁₀O₄₀ from spectral studies and elemental analysis.