OXIDATION OF DELAFOSSITE-TYPE COMPOUNDS BY CHIMIE DOUCE

Oxidation of CuLa1-xYxO2 solid solutions have been carried out with hypohalites aqueous solutions. Oxide ion intercalation end oxidation of Cu+ into Cu2+ are evidenced by color change, TGA, iodonwttric titration and magnetic measurements. Whereas for x=0 and 0.5 CuLa1-xYxO2+delta appears as a single phase, CuYO2+delta (x=1) corresponds to a two-phase mixture, with respectively low and high delta-value, the latter being isostructural with the thermally oxidized compound recently reported by Cava et al.. Comparison is stressed between the oxides obtained by oxidation at room and at higher temperatures.