초록
Isopolytungstic acid and it's salts, which are formed in sodium tungstate solutions, when acidified with perchloric acid, have been investigated by cryoscopic method. The results obtained are summarized as follows; It was not possible to measure the molecular weight of sodium isopolytungstates which are salthydrates, by means of cryoscopic method. Regardless of the concentration of solution, paratungstate and acid hexatungstate are formed at $H^+/WO_4^{2-}$ ratio of 1.15 and 1.50. It has been shown that isopolytungstic acid and it's salts are also formed at $H^+/WO_4^{2-}$ ratio of 1.30 and 1.90 and in highly concentrated solutions at 1.40 and 1.65.