P 78 Podval'naya, N. V. Composition and Formation Kinetics of Sodium Polyvanadates in Vanadium(IV, V) Solutions / N. V. Podval'naya, V. L. Volkov // Russian Journal of Inorganic Chemistry. - 2006. - Vol. 51, № 3. - P357-361 : il. - Bibliogr. : p. 360-361 (17 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ПОЛИВАНАДАТЫ Аннотация: We study how VO2+ ions affect the composition and formation kinetics of polyvanadate precipitates in solutions with 1 ≤ ç ≤ 3 at 80–90°C. The compounds have the general formula Na2.1 – xHı O31 – δ ·nH2O (0 ≤ x ≤ 1.1, 0.2 ≤ y ≤ 2.3, 0.1 ≤ δ ≤ 1.4). The maximal vanadium(IV) concentration in the precipitates (y = 2.2 and 2.3) is achieved for the V4+/V5+ ratio in the solution equal to 0.5 and 0.3 and pH of 1.7 and 3.0, respectively. The polyvanadate precipitation at pH 1.7 has a long induction period, which is not observed when V4+/V5+ > 0.02. In the solutions with pH 3.0, the precipitation occurs only when VO2+ are added. The processes are controlled by second-order reactions on the polyvanadate surface Полный текст |