M2U4O12 compounds of potassium, rubidium and thallium

Abstract Solid state reactions of M 2 CO 3 (M = K, Rb and Tl) and UO 2 with M/U = 0.5 were studied in air and in inert atmosphere at about 900°C. X-ray diffraction studies show that (1) M 2 U 4 O 13 compounds are formed when the reaction mixture is heated in air and (2) MUO 3 phases are obtained in inert atmosphere. M 2 U 4 O 13 compounds when heated in inert atmosphere form M 2 U 4 O 12 . The reactions: M 2 U 4 O 13 ⇌ Air , 700° C Ar/He , 900° C M 2 U 4 O 12 + 1 2 O 2 are reversible. X-ray powder patterns of the new M 2 U 4 O 12 compounds have been indexed. Infrared spectra and chemical analysis show the presence of lower valent uranium in these compounds.