Preparation, characterization, and some magnetic properties of Eu3VTa2O9 and Sr3VTa2O9 — New perovskites containing vanadium(II)

Two new materials of compositions Eu3VTa2O9 and Sr3VTa2O9 have been prepared and appear to contain vanadium(II), an unusual oxidation state. Powder X-ray data for both compounds can be indexed on a cubic perovskite cell with a0 = 4.001(3) Å. These cell dimensions are consistent with the ionic radius of V(II) and the cell dimensions of related Sr3(Eu3)MIITa2O9 phases. A set of weak reflections found for both materials can be indexed on an hexagonal supercell of the Ba3SrTa2O9-type (1). Further evidence for B-site ordering is provided by IR absorption spectra. Magnetic susceptibility data show the absence of a local moment on V(II). This behavior is compared with that for VOx and VTa2O6, the only other V(II) oxides yet reported.