Uniformly sized and shaped particles of metal salts are provided comprised of one or more metal cations in combination with one or more simple oxoacid anions and a general method for the controlled precipitation of said metal salts from aqueous solutions. The methods proceed via the in situ homogeneous production of simple or complex oxoacid anions in which one or more of the nonmetallic elements e.g. Group 5B and 6B (chalcogenides), and 7B (halides) comprising the first oxoacid anion undergo oxidation to generate the precipitant anionic species along with concurrent reduction of the nonmetallic element of a second, dissimilar oxoacid anion. The oxoacid anions are initially present in solution with one or more metal cations known to form insoluble salts with the precipitant anion.