Synthesis of potassium fluorophosphate hafnates at 20°C

Abstract

Potassium fluorophosphate hafnates (PFPH) K3H3Hf3F3(PO4)5 and KHf2F3(PO4)2 · 2H2O were synthesized for the first time, and a KZr2F3(PO4)2 · 2H2O phase was found to exist. The compounds were studied by crystal-optical, elemental, X-ray powder diffraction, thermogravimetric, IR spectroscopic, and electron microscopic analyses. It was found that PFPH crystallize as one-dimensional nanoparticles. The IR spectra showed that PFPH K3H3M3F3(PO4)5 (M = Zr, Hf) are crystal solvate K3M3(PO4)5 · 3HF. Annealing of K3H3Hf3F3(PO4)5 and KHf2F3(PO4)2 · 2H2O at 1000°C gives rise to mixtures that mostly contain various phosphate hafnates.