Reaction of NaBiO3 with Ba2+ Ions in an Alkaline Medium

The reaction of NaBiO3·nH2O with Ba2+ ions in an alkaline medium has been studied using X-ray diffraction and chemical analysis methods. Dark green pseudocubic phases (а 4.271–4.272 Å) of sodium‒doped matrix barium‒bismuth(III,V) oxides, with a perovskite-like structure BamBim+nOy and a ratio of Ba and Bi atoms equal to 3 : 8, 4 : 9, 1 : 2, 9 : 11, 7 : 8, and 1 : 1, are formed within 1 h at the boiling temperature of 10 М NaOH solution (140°C). In sodium-doped phases, the amount of sodium is variable and amounts to 1.4–4.7 at % of the sum of Σ(Ba, Bi). The resulting samples are characterized by the bismuth average oxidation state $$\overline {Bi} $$ 4.49–4.84, which points to a partial reduction of Bi(V) to Bi(III) during the reaction of NaBiO3·nH2O [ $$\overline {Bi} $$ 5.00(2)] with Ba2+ ions. The reaction probably proceeds through the NaBiO3 hydrolysis stage.