Synthesis and phase formation of zirconium and sodium mixed-metal phosphates with divalent d elements (zinc, cadmium, and mercury)

New zirconium mixed-metal phosphates with divalent d elements (M-II is zinc, cadmium, mercury) have been prepared. X-ray powder diffraction and IR spectroscopy were used to study phase formation in the phosphate series of the general formula (Nam-2xMxZr2-(m-1)/4)-Zr-II(PO4)(3): (Na1-2xMxZr2)-Zr-II(PO4)(3) (m = 1), (Na3-2xMxZr1.5)-Zr-II(PO4)(3) (m = 3), and (Na5-2xMxZr)-Zr-II(PO4)(3) (m = 5). Individual compounds and solid solutions crystallizing in the NaZr2(PO4)(3) (NZP) structure type have been found. The crystal parameters for them have been calculated. As a result of heterovalent substitutions of framework and extraframework cations in NZP phosphates, the phosphates can accommodate up to 25, 36, and 43 wt % zinc, cadmium, and mercury, respectively.