Phase formation in the ZrO(NO3)2-H2C2O4-KF-H2O system at 20°C

The system ZrO(NO 3 ) 2 -H 2 C 2 O 4 -KF-H 2 O was studied in the sections C 2 O 4 2− : Zr = 1 and 2. The following compounds were isolated: crystalline fluorooxalate zirconates K 3 ZrF 5 C 2 O 4 , K 2 ZrF 4 C 2 O 4 · 2H 2 O, KZrF 3 C 2 O 4 · 3H 2 O, and KZr 2 (OH) 3 F 2 (C 2 O 4 ) 2 · 4H 2 O, and also oxofluorozirconate K 2 Zr 3 O 2.5 F 9 · 7H 2 O and oxofluoride oxalate Zr 4 O 3 F 2 (C 2 O 4 ) 4 · 2H 2 O. A crystalline phase and X-ray amorphous phases of undetermined compositions were detected. All the compounds, except K 2 ZrF 4 C 2 O 4 · 2H 2 O, were obtained for the first time; the crystals KZrF 3 C 2 O 4 · 3H 2 O, KZr 2 (OH) 3 F 2 (C 2 O 4 ) 2 · 4H 2 O, and K 2 Zr 3 O 2.5 F 9 · 7H 2 O were mechanically picked up from a mixture of phases. The composition KZr 2 (OH) 3 F 2 (C 2 O 4 ) 2 · 4H 2 O is conditional. The phases were identified by X-ray powder diffraction, crystal-optical, and elemental analyses, and also by X-ray microanalysis and IR spectroscopy.