Phase formation in the ZrO(NO3)2-H3PO4-CsF(HF)-H2O system

The phase formation in the system ZrO(NO3)2-H3PO4-CsF(HF)-H2O was studied at the molar ratio CsF/Zr = 1 along the sections PO43−/Zr = 0.5 and 1.5 at a ZrO2 concentration in the initial solution of 2–14 wt %. The following compounds were isolated: Cs5Zr4F21 · 3H2O, CsZr2(PO4)3 · 2HF · 2H2O, CsZrF2PO4 · H2O, CsZr2F6PO4 · 4H2O (for the first time), CsHZrF3PO4 (for the first time), Cs0.70ZrF(PO4)1.23 · nH2O, and CsHZr2F2(PO4)2.66 · nH2O. The compositions of CsZrF2PO4 · H2O, Cs0.70ZrF(PO4)1.23 · nH2O, and CsHZr2F2(PO4)2.66 · nH2O are conditional. All the compounds were characterized by crystal-optical, X-ray powder diffraction, thermal analyses, and IR spectroscopy. The formula CsHZrF3PO4 was established by energy-dispersive analysis with a LEO-1450 scanning electron microscope and an MS-46 CAMECA X-ray microanalyzer.