P 78 Podval'naya, N. V. Hydrolytic Precipitation of Magnesium Polyvanadates in Vanadium (IV, V) Solutions / N. V. Podval'naya, V. L. Volkov // Russian Journal of Inorganic Chemistry. - 2010. - Vol. 55, № 2. - P305-311 : il. - Bibliogr. : p. 311 (19 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ПОЛИВАНАДАТ МАГНИЯ -- РАСТВОРЫ ВАНАДИЯ Аннотация: The phase and chemical composition of precipitates formed in Mg(VO3)2–VOSO4–H2O system at initial pH from 1 to 7 and temperature from 80 to 90°C was studied. Polyvanadates of variable composition MgxV(4+)V(5+)12-y O31 – δ · nH2O (0.7 ≤ x ≤ 1.3, 1.2 ≤ y ≤ 2.4, 0.7 ≤ δ ≤ 1.4) were formed at pH from 1 to 4 and V4+/V5+ ratios from 0.43 to 9. Compounds with the general formula MgxV V O16 – δ. nH2O (0.7 ≤ x ≤ 0.65, y = 1.0, 0.8 ≤ δ ≤ 0.85) were formed at pH from 6.0 to 7.0 and V4+/V5+ ratios from 0.11 to 0.25. The maximum V4+ concentration (y = 2.4) in the precipitates was achieved at the VV4+/V5+ solution ratio of 1.0 and H = 3. The precipitates in solutions with pH 3 were formed only upon addition of VO2+ ions with the maximum rate at a V4+/V5+ ratio of 0.33. These processes were limited by second order reactions on the surface of polyvanadates Полный текст |