Methods for identification of Bi (v) and unusual oxygen valence states in BaBiO3 and superconducting oxides of K - Ba - Bi - O system

Abstract

A radically different behavior of oxides — BaBiO 3 and superconducting K n Ba m Bi m+n O y (n = 1, 2, 3; m = 1, 3, 4, 5) — and BaO 2 peroxide is observed in reactions of hydrolysis and acid dissolution. Chemical tests and potentiometric analysis did not reveal peroxide-ions present in BaBiO 3 and K n Ba m Bi m+n O y , as well as in the products obtained by oxide treatment with water, alkali and acids. Most probably this indicates to the absence of unusual valence states (UVS) of oxygen in the form of peroxide- and superoxide-ions in the structure of oxides under study. Data of potentiometric titration (PT) also proved the absence of oxygen UVS and bismuth in the oxidation state of < + 3 in superconducting K n Ba m Bi m+n O y oxides. A number of agents (Mn (II), Cr (III), Cu (II), Ce (III) salts, Arnold’s base, methyl red, chromazurol S, arsenazo III, indigo carmine, and thoron) are revealed which provide Bi (V) detection in BaBiO 3 and K n Ba m Bi m+n O y . An experimentally observed behavior of the oxides in chemical reactions regarding agents-reductants is attributed to Bi (V) present in their structure which is much stronger oxidizer compared to peroxide dioxygen.