STRUCTURE AND LUMINESCENT PROPERTIES OF 3 NEW SILVER LANTHANIDE MOLYBDATES

Three new compounds AgLnMo(2)O(8) (Ln = Eu, Gd, Tb) crystallize with a tetragonal scheelite-type structure characterized by MoO4 tetrahedra. The IR spectra show three absorption bands, which correspond respecti vely to the nu(1), nu(2), and nu(3) modes of the tetrahedral-MoO42- gr oups. The emission of AgGdMo2O8 shows the band of the MoO42- groups ar ound 600 nm wavelength with very weak intensity. Both AgEuMo2O8 and Ag TbMo2O8 emit intensely, and the concentration quenchings of both Eu3and Tb3+ luminescences are very weak. For all compounds, Ag+ luminesce nce is not observed. (C) 1996 Academic Press, Inc.