Thermal stability of potassium fluorooxalatozirconates

Аннотация

Thermal decomposition of fluorooxalatozirconates (FOxZs) K₃ZrF₅C₂O₄, K₂ZrF₄C₂O₄ ⋅ 2H₂O, KZrF₃C₂O₄ ⋅ 3H₂O, and Zr₄O₃F₂(C₂O₄)₄ ⋅ 2H₂O in air flow is studied. Crystalline K₂ZrF₄C₂O₄ and KZrF₃C₂O₄ are detected. The decomposition onset temperature of anhydrous products goes down as the K/Zr molar ratio decreases. Disproportionation of potassium FOxZs both at the oxalate group yielding K₂ZrF₄C₂O₄ and ZrO_2–x/2F_x, K₂C₂O₄ and K₃ZrF₇ and at fluorine yielding K₃ZrF₇ and ZrO₂ takes place. FOxZs can be used as precursors to produce fine-grained ZrO₂ (baddeleyite).