SYNTHESIS, CRYSTAL STRUCTURE AND PHOTOLUMINESCENCE PROPERTIES OF A NEW RARE-EARTH CARBONATE Na3Eu(CO3)3·6H2O

A new sodium europium carbonate hydrate, Na3Eu(CO3)(3)center dot 6H(2)O, has been prepared using the hydrothermal method, and its structure was determined by single crystal X-Ray diffraction analysis for the first time. It crystallizes in the polar hexagonal space group P6(3) with a = 11.382(9)angstrom, c = 5.989(5) angstrom,V = 672.06(9) angstrom(3), Z = 2, Mr = 509.06, Dc = 2.516 g/cm(3), F(000) = 492, mu(MoK alpha) = 4.84 mm(-1), R-1 = 0.015 and wR = 0.038. The structure features a three-dimensional(3D) framework composed of planar (CO3)(2-) triangles, Eu3+ ions and Na+ ions, which delimits 1D infinite chains with a hexangular star appearance along the c-axis. The IR spectrum and the self-activated photoluminescence properties were studied. Under the excitation of near UV light (395nm), it shows strong red emission at 618 nm with a lifetime of 348.7 mu s. Present research indicates that Na3Eu(CO3)(3)center dot 6H(2)O is a promising red phosphor for white light-emitting diodes.