A KINETIC AND SPECTROPHOTOMETRIC STUDY OF FORMATION AND REDUCTION OF A PHOSPHORUS-BISMUTH DIMERIC HETEROPOLYMOLYBDATE

A spectrophotometric procedure has been used to determine the composition of a unique, mixed bismuth-phosphorus, dimeric heteropolymoiybdate. A stoichiometry study indicated that the Mo:P:Bi ratio in the complex was 18:1:1. The complex was more stable in perchloric acid solutions than 12-molybdophosphoric acid but it was reduced considerably more easily to a heteropoly blue. The experimental rate law is in good agreement with a mechanism involving an equilibrium step forming the heteropoly acid followed by a reduction step. The initial reduction of the complex by ascorbic acid apparently proceeded by a 2-electron, acid independent step. © 1969, American Chemical Society. All rights reserved.