Sulphur dioxide reacts with a solution of cupric acetate in acetic acid to form colourless, hexagonal leaflets of Cuprous sulphite, Cu2SO3,½H2O. In aqueous solution sulphur dioxide converts this substance into a red, prismatic form, Cu2SO3,H2O, also formed by the action of this gas on alkali cuprous sulphites in presence of water. The sulphite is capable of forming complex ammonium derivatives of the type Cu2SO3,(NH4)2SO3. |