Reactions of copper in molten alkali-metal nitrite

Abstract

When molten NaNO₂ is electrolysed between copper electrodes, a yellow precipitate which contains copper(1) forms at the cathode.It seems probable that a cuprite with the empirical formula Na₂O,Cu₂O,H₂O is initially formed and is then slowly oxidized either by species present in the melt or by air. If sufficient Na₂O₂ is added to saturate the melt (i.e., solid Na₂O₂ is present),the precipitate partly dissolves to form an orange-red solution which forms a green solid on freezing. This may contain a copper(11) or copper(111) cuprate.