Formation and characterization of the non-crystalline lanthanoid(III) hydrate salts of lacunary heteropolytungstates, SiW_(11)O_(39)~8- AND P_2W_(17)O_(61)~(10)-

摘要

When aqueous solutions which contain Ln~(3+), K~+ and lacunary heteropolytungstate ions, SiWnO_(39)~8 -orP_2Wi_7O_6]~(10) , at high concentrations are cooled to nearly 0 deg C, the solutions separate into two layers with a clear boundary. The lower layers are very viscous, of high densities, sround 3 gcm~ -3. The separation takes place for all the trivalent lanthanides when K~+ exists as the univalent cation. When Na~+ or Li~+ is used instead of K~+, the solutions just become very thick. When Na~+ is mixed with K~+ in certain ratios, two layer formation is observed. The oil-like materials are considered as liquid hydrate salts with average chemical compositions Na_vK_yLn[SiWi_(11)O_(39)_2.nH_2 O, where x was varied from 0 lo 5.5 and n is the molar number of water, ~100.