Magnesium Thiosulphate, MgS₂O₃

Magnesium Thiosulphate, MgS₂O₃.6H₂O, crystallises in rhombic prisms which are stable in air, readily soluble in water, and precipitated from a concentrated solution by alcohol. It has been prepared by digesting a solution of magnesium sulphite with sulphur, and by decomposing magnesium sulphate in solution with barium thiosulphate. The double salts MgS₂O₃.K₂S₂O₃.6H₂O and MgS₂O₃.(NH₄)₂S₂O₃.6H₂O have been prepared.