INVESTIGATIONS OF PHASE EQUILIBRIUM IN THE SYSTEMS M₂O₃-P₂O₅-H₂O, M=Al, Ga, In AND Tl(III) BY THIN LAYER METHOD: COMPOUNDS FORMATION AND PROPERTIES OF NOVEL PHOSPHATES

Abstract

Phase equilibrium in the systems M₂O₃-P₂O₅-H₂O, M=Al, Ga, In and Tl(III) (molar ratio P₂O₅: M₂O₃= (3÷10):1) have been studied within the temperature range of 25-300°C by thin layer method. The crystallization fields diagrams of stable phases were plotted. Preparation conditions of a number of novel phosphates, MH₉(PO₄)₄ (M=Al, Ga, In), M(H₂PO₄)₃ (M=Ga, In, Tl), M₃H₁₅(PO₄)₈ 5H₂O (M=Ga, In), MH₃(PO₄)₂ 4H₂O(M=Ga, Tl), T1H₃(PO₄)₂ nH₂O (n=0, 1, 2, 4), Ga(H₂PO₄)(H₂P₂O₇), T1HP₂O₇, In₃H₇(P₂O₇)₄, InH₂P₃O₁₀, In₂H₂P₂O₇(P₄O₁₂), and Tl(PO₃)₃ were elaborated. Main regularities in formation of compounds in the studied systems are discussed.