SYNTHESIS STUDY OF THE MONOLACUNARY KEGGIN K7PMo11O39

The synthesis of monolacunary Keggin K7PMo11O39 was effectuated in this article using three different methods and were found arguments for one by one. A direct combination of simple oxoanions in water solution, under rigorous pH control in HCl medium was used in first method. The second method started from complete Keggin structure, H3PMo12O40∙12H2O, when a unity of molybdate was put out and the third technique was based a combination reaction between trilacunary Na3H6PMo9O34 and two molybdate unities at optimal pH. K7PMo11O39 resulted from all synthesis methods was analysed with UV-VIS, thermogravimetry, conductometry, potentiomery and AAS methods for determination of the chemical composition and structure.