S 98 Synthesis and Properties of M2V8O21 (M=K, Tl) Octavanadates and K2-xTlxV8O21 (0 ≤ x ≤ 2) Solid Solutions / V. N. Krasil'nikov, L. A. Perelyaeva, I. V. Baklanova, L. Yu. Buldakova, M. Yu. Yanchenko // Russian Journal of Inorganic Chemistry. - 2009. - Vol. 54, № 10. - P1537-1542 : il. - Bibliogr. : p. 1542 (15 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ОКТАВАНАДАТЫ -- ТВЕРДЫЕ РАСТВОРЫ Аннотация: Formation parameters and properties of M2V8O21 octavanadates where M = K and Tl were studied using X-ray powder diffraction, microscopy, thermogravimetry, vibrational spectroscopy, EPR, and voltammetry. Original synthesis processes for these compounds were developed; their thermal stability parameters were determined. Potassium and thallium(I) octavanadates were shown to form complete solid solutions with each other. Potassium octavanadate in air is stable to 450°C; above this temperature, it transforms, on account of partial reduction of vanadium, to vanadium bronze by the reaction K2V8O21<--> K2V8O20.8 + 0.1O2. The K2V8O20.8 percentage in the sample increases with rising temperature. The substitution of small thallium amounts for potassium (x ≥ 0.025) enhances the stability of the phase until it melts at ~525°C. Полный текст |