SYNTHESIS BY CHIMIE-DOUCE AND CHARACTERIZATION OF INDIUM VANADATES

Using boiling solutions of xerogel (V2O5 1.6H2O) or of vanadic acid mi xed with solutions of indium nitrate, the totality of the In2O3-V2O5 s ystem has been explored. Experimental conditions, especially the time of stirring, have a significant effect upon the composition, the stabi lity and the crystallinity of the synthesized compounds. The following hydrated amorphous phases were obtained: InVO4 2.4H2O, InVO4 1H2O and In2 V4O13 7H2O. These compounds, after the loss of water around 100-d egrees-C, lead to three anhydrous amorphous phases, InVO4 a, InVO4 b a nd ln2V4O13 which are the precursors respectively of crystallized InVO 4 I, InVO4 III and ln2V4O13. Crystallographic characteristics of the crystallized compounds were deduced from their powder patterns. Compar isons were also made between InVO4 III and InVO4 III obtained by heat ing of InVO4 I.