Synthesis and characterization of new rocksalt superstructure type layered oxides Li 4.5 M 0.5 TeO 6 (M(III) = Cr, Mn, Al, Ga)

Abstract Oxides of stoichiometry Li 4.5 M 0.5 TeO 6 (M(III) = Cr, Mn, Al, Ga) have been synthesized by the solid state method and are characterized for the first time. The Rietveld refinements of the PXRD measurements confirmed the structure to be similar to the Li 3 (Li 1.5 Fe 0.5 Te)O 6 (S.G. C2/m ; a ∼ 5.183 A; b ∼ 8.885 A; c ∼ 5.168 A; β ∼ 110.6°) oxide. The oxides undergo ion-exchange reactions with Ag + ions. UV–vis diffuse reflectance measurements showed the variation in the band gaps in consistent with the colors observed from brown, brick red to white respectively for Cr 3+ , Mn 3+ and Al 3+ or Ga 3+ containing oxides. The stabilization of Li 4.5 M 0.5 TeO 6 (M(III) = Cr, Mn, Al, Ga) obtained by varying the alkali metal (Li + ) ions together with other M 3+ ions and Te 6+ ions forming the edge shared octahedral layer in the rocksalt ordered structures yet again shows the rich compositional versatility of AMO 2 type oxides.