Triple phosphates of calcium, sodium and trivalent elements with whitlockite-like structure

Triple phosphates of calcium, sodium and trivalent elements (Eu, Nd, Fe) in Ca-3(PO4)(2)-RPO(4)-Na3PO4 systems were predicted on the basis of crystal chemistry data and synthesized. The obtained phases were studied by XRD, IR-spectroscopy and emission spectroscopy under Sr-90-Y-90 and lambda = 380 nm excitation. The only phosphates with the whitlockite-like structure appear within the range of Ca-3(PO4)(2)-Ca(9)Na(1.5)R(0.5)(PO4)(7)-Ca10Na(PO4)(7) composition. The emission spectra of phases with europium under Sr-90-Y-90 excitation consist of transition lines D-5(0)--> F-7(j) in EU(3+) and two broad bands of inherent luminescence of the matrix with maximums at similar to 360 and similar to 510 nm.