Thermal stability and X-ray luminescence properties of cesium fluorophosphatohafnates

The thermal stability of cesium fluorophosphatohafnates (crystalline CsHf2F2(HPO4)(2)PO4 center dot 2H(2)O, CsHfF2PO4 center dot 0.5H(2)O, CsHf2F6PO4 center dot 4H(2)O and X-ray amorphous Cs2Hf3O1.5F5(PO4)(2) center dot 5H(2)O, Cs5H4Hf3F7(PO4)(3.66)(NO3)(3) center dot 5H(2)O) was determined. The weight ratios Cs+/Hf and PO (4) (3-) /ZrHf in CsHf2F2(HPO4)(2)PO4 center dot 2H(2)O were confirmed by identifying the calcination production CsHf2(PO4)(3) (similar to 1000A degrees C). A new crystalline compound CsHf2F(HPO4)(PO4)(2) was found by thermogravimetric and X-ray powder diffraction analysis during heating. A new method for hydrothermal synthesis of CsHf2(PO4)(3), which was different from the already known one, was proposed. It was ascertained that CsHf2(PO4)(3) possesses a significant X-ray luminescence; whereas in fluorophosphatehafnates show low luminescence intensity.