Interaction of Ag ions with a vanadium pentoxide hydrate - Formation of silver vanadate at low temperature

Reactions between V2O5. nH(2)O sol and Ag+ solution were investigated and new conventional reaction processes to produce silver vanadate bronzes were found. Reactions were surveyed as a function of the concentration ratios of Ag and V, and the reaction regions were divided into 4 parts dependent upon the reaction products. System 1: ion-exchanged sediment to produce beta-Ag0.35V2O5; System 2: needle-like alpha-AgVO3 and hydrate to produce Ag2-xV4O11 upon heating; System 3: new fine needle-like particle and small proportions of various dendrite crystallites; System 4: hydrate to produce beta-AgVO3 upon heating. The new needle-like particle of system 3 was analyzed by use of electron diffraction and XRD and found to be monoclinic, a = 32.96 Angstrom, b = 2.60 Angstrom, c = 3.62 Angstrom, and beta = 91.88 degrees. The material is named delta-AgVO3. beta-Ag0.35V2O5 and Ag2-xV4O11 were reversibly crystallized after melt. beta-AgVO3 was crystallized when the melt was cooled slowly, while alpha-AgVO3 was crystallized when quenched rapidly. (C) 2000 Kluwer Academic Publishers.