Molten Potassium Pyrosulfate: Reactions of Lanthanum Metal and Six of Its Compounds

Abstract

The reactions of lanthanum metal, La₂O₃, La(OH)₃, La(NO₃)₃.6H₂O, La₂(CO₃)₃.3H₂O, LaCl₃ and LaCl₃.7H₂O with molten K₂S₂O₇ were studied. The metal reacted with K₂S₂O₇ to produce La₂(SO₄)₃, K₂SO₄ and SO₂. Lanthanum(III) oxide was converted into La₂(SO₄)₃, as were La(OH)₃, La(NO₃)₃.6H₂O, La₂(CO₃)₃.3H₂O, LaCl₃ and LaCl₃.7H₂O but with the evolution of H₂O, NO₂ + O₂ + H₂O, CO₂ + H₂O, Cl₂ + SO₂ + S and Cl₂ + SO₂ + H₂O + HCl respectively. K₂S₂O₇ was converted into K₂SO₄ in the reactions. Reaction pathways have been suggested to explain the final products. The temperatures and stoichiometries of the reactions have been established.