Strontium Sulphite, SrSO₃

Strontium Sulphite, SrSO₃, may be obtained by the precipitation of strontium chloride with an alkali sulphite. It is also formed when strontium oxide is heated with sulphur dioxide at 230°-290° C. Several weeks are required in order to complete the reaction. The salt is anhydrous and readily crystallises in flattened prisms. It is slowly oxidised to sulphate by air. On heating, it is transformed into a phosphorescent mixture of strontium sulphide and sulphate. The solubility of the sulphite in water is less than that of the sulphate, being only 33 mgm. per litre at ordinary temperatures.