Preparation, structure and some physical properties of scheelite-related AgLnMo 2O 8 compounds

Abstract

We present the synthesis of the AgLnMo 2O 8 oxides with Ln = La-Nd, Sm, Gd, Tb and Y. These compounds represent a scheelite-related structure type characterized by MoO 4 2− tetrahedrons. The IR spectra show three transmittance bands in the region of 1000-400 cm −1, which correspond respectively to the ν 1, ν 2, and ν 3 modes of the tetrahedral MoO 4 2− groups. All of AgLnMo 2O 8 are insulator materials at room temperature. The temperature dependence of the magnetic susceptibilities of AgLnMo 2O 8 (Ln = Ce-Nd, Sm, Gd, Tb) show Curie-Weiss Law behaviors with two anomalies occurring at low temperature, whereas AgLaMo 2O 8 and AgYMo 2O 8 both exhibit diamagnetic properties as expected. The magnetic moments at room temperature fit very well with those corresponding to rare earth sesquioxides. This suggests that rare earth ions exist in +3 oxidation state in all AgLnMo 2O 8 compounds.