Acid Leaching of$LiMW{_2}0{_8} (M =Al, Fe)$ in Aqueous $HNO{_3}$:Formation of $WO{_3}.H{_2}O$ and $wo{_3}.1/3H{_2}O$

WO3 . H2O and WO3 . 1/3H(2)O are obtained by acid leaching of LiMW(2)O(8) (M=Al, Fe), The monohydrate is obtained by leaching in 6 mol l(-1) HNO3, and the one-third hydrate by leaching in concentrated HNO3. On dehydration, the monohydrate transforms to the monoclinic ReO3-like WO3, whereas the one-third hydrate transforms to hexagonal WO3. The present work, together with our previous work on the leaching of LiVWO6 (Chem. Mater., 1994, 6, 373), shows that acid leaching is not likely to be a topochemical reaction, since the structure of the solid products obtained is not determined by the structure of the starting material