Abstract:

Through ion exchange reaction together with the use of electron pair donor organic reagents, active white powdery tungstic oxide hydrate (abbr. WPTA) can be separated into mutually convertible deca- and hexa-tungstates. A brief sketch of procedures is given in scheme 1. The success of the above mentioned method in getting deca- and hexa-tungstates promptly led to our new method of preparing deca- and hexa-tungstates through oxidation of tungsten carbide with hydrogen peroxide. Many applications of WPTA, together with different polytungstates prepared there from,as an extension of those listed in our previous report^[3], with significant new addtions including photo-chromic polytungstates, have been hereby presented. The acidification scheme connecting sodium tungstate to yellw tungstic acid has beenproposed through the incorporation of deca- and hexa-tungstates. A Brief sketch is given is scheme 2.

Key words: Active tungstic acid, Deca-tungstate, Hexa-tungstate, Photo-chromic polytungstate, Review