Synthesis and characterization of the new mixed oxides M(VTe)O6(M = K, Rb, or Cs)

Abstract

New mixed oxides of the pyrochlore type of composition M(VTe)O₆ have been synthesized by reacting V₂O₅, Te(OH)₆, and MNO₃(M = K, Rb, or Cs)(molar ratio 0.5:1:1) at 673 K. Characterization of these materials has been carried out by X-ray powder diffraction, giving cubic symmetry (space group Fdm) and lattice parameters a= 10.008(1)(M = K), 10.036(1)(M = Rb), and 10.483(1)Å(M = Cs). The atomic positions and R discrepancy factors were also calculated. Thermal analysis of the initial mixtures allowed the interpretation of the transformations involved up to decomposition of the pyrochlores. l.r. spectra are discussed on the basis of the structural type.