PREPARATION, STRUCTURE AND SOME PHYSICAL-PROPERTIES OF SCHEELITE-RELATED AGLNMO(2)O(8) COMPOUNDS

We present the synthesis of the AgLnMo(2)O(8) oxides with Ln = La-Nd, Sm, Gd, Tb and Y. These compounds represent a scheelite-related struct ure type characterized by MoO42- tetrahedrons. The IR spectra show thr ee transmittance bands in the region of 1000-400 cm(-1), which corresp ond respectively to the nu(1), nu(2), and nu(3) modes of the tetrahedr al MoO42- groups. All of AgLnMo(2)O(8) are insulator materials at room temperature. The temperature dependence of the magnetic susceptibilit ies of AgLnMo(2)O(8) (Ln = Ce-Nd, Sm, Gd, Tb) show Curie-Weiss Law beh aviors with two anomalies occurring at low temperature, whereas AgLaMo 2O8 and AgYMo2O8 both exhibit diamagnetic properties as expected. The magnetic moments at room temperature fit very well with those correspo nding to rare earth sesquioxides. This suggests that rare earth ions e xist in +3 oxidation state in all AgLnMo(2)O(8) compounds.