[en] Interaction (solubility) of Fe₂O₃, Cr₂O₃, NiO, MgO, Al₂O₃, and ZrO₂ with potassium fluorozirconate K₃ZrF₇ has been studied at 1000 deg C. Interaction of MgO and Al₂O₃ with K₃ZrF₇ has been studied by isothermal saturation; interaction of other oxides by the addition method. To elucidate the mechanism of interaction, X-ray phase analysis has been used. It has been established that interaction of oxides Al₂O₃, MgO, and Fe₂O₃ with melted potassium heptafluorozirconate is accompanied by chemical interaction. Nickel and chromium oxides practically do not interact with K₃ZrF₇